LEASE

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                                                                   Exhibit 10.31

                                      LEASE

                               Boulder Tech Center

      THIS LEASE ("Lease"), dated May 14, 1999, is between MUM IV, LLC, a
Colorado limited liability company ("Landlord") and Helix Technology
Corporation, a Delaware corporation ("Tenant").

      For and in consideration of the covenants and agreements herein contained,
Landlord and Tenant hereby agree as follows:

      Section 1. ADDITIONAL DEFINED TERMS

      In addition to those terms defined in the introductory paragraph of this
Lease, the following terms shall have the following meanings when used in this
Lease:

      (a) Estimated Operating Cost: An amount equal to Two Dollars and
Forty-five Cents ($2.45) per square foot per calendar year, which represents an
estimate of the Operating Cost for the entire year in which the Term of this
Lease begins.

      (b) Base Rent: The annual amount of rent payable with respect to each
Lease Year during the term of this Lease payable as set forth in Section 4(a).
The amount of the Base Rent for the first Lease Year shall be Eight Dollars and
Ninety-Five Cents ($8.95) per square foot of Rentable Area of the Premises. The
amount of the Base Rent for all Lease Years after the first Lease Year shall be
calculated in the manner set forth in Section 4(a). During each Lease Year, Base
Rent shall include the previous year's Base Rent and any rental increase from
the previous year.

       (c) Building: The building to be constructed by Landlord upon the Premises
pursuant to Section 10 of this Lease, the plans and specifications for which are
shown on Exhibit B attached hereto, which building shall contain approximately
60,906 (sixty thousand nine hundred six) Rentable Square Feet and shall have two
(2) floors.

      (d) Commencement Date: The date the Term of this Lease commences as
determined in accordance with provisions of Section 30.

      (e) Default Rate: An annual rate of interest equal to fifteen percent
(15%).

      (f) Lease Year:

            (i) For the First Lease Year, the period beginning on the
Commencement Date and ending on the last day of the same calendar month in which
the Commencement Date occurred in the next calendar year; and

            (ii) For Lease Years after the First Lease Year, the twelve-month
period beginning on the next day following the expiration of the preceding Lease
Year.

      (g) Operating Cost: As defined in Section 6(b).

      (h) Parking Lot: The on-grade parking lot to be constructed by

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Landlord upon the Premises pursuant to Section 10 of this Lease and as shown on
Exhibit B attached hereto, containing not less than 150 parking spaces for use
by passenger motor vehicles.

      (i) Premises: That certain parcel of real property described as: Lot 2E,
Block 3, REPLAT E, BOULDER TECH CENTER, County of Boulder, State of Colorado, as
shown on the recorded plat attached hereto as Exhibit A and incorporated herein
(such plat has been recorded on Planfile P-39, F-1, #23) together with the
Building, the Parking Lot and all other improvements from time to time hereafter
located on such parcel of real property and any and all appurtenant rights
relating thereto.

      (j) Term: The period beginning at noon on the Commencement Date and ending
at 11:59 p.m. on the last day of the calendar month in which the fifteenth
(15th) anniversary of the Commencement Date occurs.

      (k) Rentable Area or Rentable Square Feet: The sum of the area of each
story of the Building expressed in square feet measured from the outside of the
exterior walls.

      Section 2. LEASE OF PREMISES

      Landlord hereby leases to Tenant, and Tenant hereby leases from Landlord,
the Premises. The Premises are leased on the terms and conditions set forth in
this Lease.

      Section 3. TERM

      The term of this Lease shall be as set forth in Section 1(j), unless
sooner terminated or extended pursuant to the terms of this Lease.

      Section 4. RENT

      (a) Tenant shall pay Landlord during each Lease Year the Base Rent, in
equal monthly installments in the amount of one-twelfth of the Base Rent on the
Commencement Date and on the first day of each succeeding calendar month during
the Term of this Lease; provided that the rent payable on the Commencement Date
shall be prorated for the remaining days left in the calendar month in which the
Commencement Date occurs. Except as expressly set forth in this Lease to the
contrary, all payments of Base Rent shall be paid in advance, without notice,
set-off or deduction, in lawful money of the United States, at the address of
Landlord set forth in Section 40 of this Lease, or at such other place as
Landlord may from time to time designate in writing.

      The amount of the Base Rent for each year after the first Lease Year shall
be increased. The Base Rent shall increase at such times by an amount determined
by multiplying the amount of the Base Rent in effect for the preceding Lease
Year by an escalation factor which factor shall be calculated in the following
manner.

            (i) For the Lease Years two through 5 of the term of the Lease the
escalation factor shall be two percent (2%) annually.

            (ii) For the 6th through the 10th years of the Lease the escalation
factor for each Lease Year shall be calculated in the following manner: 1)
Calculate the average annual change in Lease Years 3, 4 and 5 of the All Items
Revised Consumer Price Index for All Urban Consumers, CPI-U, Denver

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(1982-84 equals 100), as determined by the United States Department of Labor,
Bureau of Labor Statistics ("CPI"). 2) Add the annual increase used for the
initial five Lease Years (two percent (2%)) to the average increase calculated
in 1) above, but if the average increase calculated in (1) above is higher than
10%, use 10% as the calculation of (1) above; 3) Divide the sum by two. This
result will be the escalation factor for Lease Years 6 through 10. By way of
example, if the average annual CPI increase during Lease Years 3, 4 and 5 was
1%, you would add 2% to 1% for a sum of 3%, then divide that sum by two, for an
annual increase in the rental rate for Lease Years 6 through 10 of 1 1/2 % per
year.

            (iii) For the 11th through the 15th Lease Years of the Lease the
escalation factor for each Lease Year shall be calculated in the following
manner: 1) Calculate the average annual change in Lease Years 8, 9 and 10 of the
All Items Revised Consumer Price Index for All Urban Consumers, CPI-U, Denver
(1982-84 equals 100), as determined by the United States Department of Labor,
Bureau of Labor Statistics. 2) Add the annual increase used for the Lease Years
6 through 10 to the average increase calculated in 1) above, but if the average
increase calculated in (1) above is higher than 10%, use 10% as the calculation
of (1) above; 3) Divide the sum by two. This result will be the escalation
factor for Lease Years 11 through 15. By way of example, if the average annual
CPI increase in Lease Years 8, 9 and 10 was 20% and using the previous example's
result where the annual increase for Lease Years 6-10 was 1 1/2%, you would add
1 1/2% to 10% for a sum of 11 1/2%, then divide that sum by two, for an annual
increase in the rental rate for Lease Years 11-15 of 5 3/4%.

      In no event shall the Base Rent for any Lease Year ever decrease below any
previous Lease Year's Base Rent.

      (b) If the index specified in Section 4(a) above is discontinued in its
current form, or if the basis on which it was calculated should be revised, an
appropriate conversion of the revised index to a common base will be made upon
conversion factors published by the Bureau of Labor Statistics or upon
conversion factors otherwise made available.

      (c) For Lease Years 6 through 15, in the event that Tenant has not been
notified of the escalation factor and the resulting adjustment in Base Rent by
the first day of a Lease Year, the first monthly rental payment of Base Rent
which includes new increased rent shall also include the new increased rent, if
any, for each month in the then current Lease Year which elapsed prior to
Tenant's receipt of Landlord's notice. The Base Rent due hereunder shall be
apportioned for any fractional calendar months at the beginning and end of the
Term of this Lease and any renewals and extensions thereof.

      (d) In addition to the Base Rent (as increased each Lease Year), Tenant
shall pay Landlord in monthly installments simultaneously with payments of the
Base Rent, one-twelfth (1/12th) of the Estimated Operating Cost (or new estimate
of Operating Cost) determined as set forth in Section 6, and such other charges
as are required by the terms of this Lease to be made by Tenant, including, but
not limited to, 100% of the Operating Cost adjustment. Any such adjustment or
charge shall be deemed to be additional rent and shall be payable in the manner
provided for the payment of Base Rent and shall be recoverable as Base Rent, and
Landlord shall have all rights against Tenant for default in payment thereof as
in the case of arrears of Base Rent.

      (e) In the event the Building as constructed by Landlord is not
substantially in accordance with the plans and specifications provided in

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Exhibit B and as a result the Rentable Area of the Building is less than 60,906
Rentable Square Feet, Tenant shall have the right within thirty (30) days
following the Commencement Date to cause the Rentable Area of the Building to be
measured by the Architect (as defined in Section 10), at Landlord's expense, and
the Base Rent hereunder shall be reduced on a pro rata basis by the same
percentage amount by which the Rentable Area is less than 60,906 square feet.
Promptly after such measurement, Landlord and Tenant shall enter into an
amendment to this Lease documenting the Base Rent to be paid hereunder.

      Section 5. USE

      (a) Tenant shall use and occupy the Premises for manufacturing,
warehousing, offices and other uses incidental thereto and for no other purpose
without Landlord's consent, which shall not be unreasonably withheld, delayed or
conditioned and shall be deemed to be given if Landlord has not responded within
ten (10) days of Tenant's request for such consent. Tenant shall use the
Premises in a careful, safe and proper manner and shall not use or permit the
Premises to be used for any purpose prohibited by the certificate of occupancy
issued for the Premises or the laws of the United States or the State of
Colorado, or the ordinances of the County of Boulder. Neither Tenant nor
Landlord shall do or permit to be done any act or thing upon the Premises which
shall or might subject the other to any liability or responsibility for injury
to any person or persons or to property by reason of any business or operation
carried on upon the Premises or for any reason.

      (b) In the event that any official shall hereafter at any time contend or
declare by notice, violation, order or in any other manner whatsoever that the
Premises are used for a purpose which is a violation of any permit, certificate
of occupancy, statute, ordinance or other requirement of law applicable to the
Premises, Tenant shall, upon ten (10) days' written notice from Landlord,
immediately discontinue such use of the Premises.

       (c) Tenant, at its sole expense, shall comply with all laws, orders and
regulations of federal, state, county and municipal authorities, and with any
direction of any public officer or officers, pursuant to law, which shall
declare any violation or impose any order or duty upon Landlord or Tenant with
respect to the Premises, or the use or occupation thereof. Notwithstanding the
foregoing, Tenant shall not be obligated to comply with any such laws, orders,
or regulations, including but not limited to the Americans With Disabilities
Act, which (a) relate to the design or construction of the Premises, (b) relate
to the structural portions of the Premises, or (c) may require structural
alterations, structural changes, structural repairs or structural additions, all
of which shall be the obligation of Landlord at its sole cost and expense;
provided, however, if such laws, orders or regulations relate to the specific
type or nature of the business being conducted or to be conducted by Tenant upon
the Premises or to the specific accommodations made or to be made for certain of
Tenant's employees as opposed to being related to industrial or office
buildings, generally, Tenant shall nevertheless be required to comply with them.
Without limiting the generality of the foregoing, but subject to the proviso in
the preceding sentence, Landlord, at it sole cost and expense, shall be
responsible for complying with the applicable provisions of the Americans With
Disabilities Act and the regulations and Accessibility Guidelines for Buildings
and Facilities issued pursuant thereto, as same may be amended (collectively,
the "ADA"), relating to (i) the design and construction of the Premises and the
work within the Premises to be performed by Landlord pursuant to this Lease, and
(ii) the structural portions of the Premises (collectively, "Landlord's Work").

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      Section 6. OPERATING COST ADJUSTMENT

      (a) If in any calendar year the Operating Cost is greater than the
Estimated Operating Cost, Tenant shall pay to Landlord as additional rent an
amount equal to such excess. Any amount payable by Tenant to Landlord under this
Section 6 shall be paid within thirty (30) days after written notice thereof by
Landlord, such notice to be given by Landlord not later than March 31 of each
calendar year. Landlord may, either prior to the beginning of or during any
calendar year, compute a bona fide estimate of Operating Cost for such calendar
year. Upon receipt of written notice thereof, Tenant shall pay to Landlord, in
monthly installments simultaneously with payments of Base Rent under Section
4(a), one-twelfth of such new estimate of Operating Cost. An annual adjustment
shall be made between the parties within thirty (30) days after Landlord's
determination of Operating Cost. Any amounts of excess estimated Operating Cost
which Landlord is required to return may be offset by accrued amounts payable by
Tenant to Landlord. If the term of this Lease ends before the end of a calendar
year, any amount payable by Tenant or Landlord in respect of that year under
this Section 6 shall be adjusted proportionately on a daily basis utilizing the
previous year's determination of Operating Costs and the obligation to pay such
amount shall survive the expiration or earlier termination of this Lease.

      (b) As used in this Lease, "Operating Cost" means an amount per calendar
year (projected to an annual figure for the calendar year in which the Premises
is first occupied) which represents the actual Operating Cost for any calendar
year during the Term of this Lease. The Operating Cost shall be determined by
Landlord and shall be equal to the sum of the items of cost listed in Section
6(b)(i) and Section 6(b)(ii) but not the items listed in Section 6(b)(iii) in
respect of a calendar year:

            (i) All general and special real estate taxes, special assessments,
assessments for improvements, special district or improvement district
assessments, water charges, sewer charges, vault charges and other ad valorem
taxes, rates, levies and assessments payable in respect of the Term upon or in
respect of the Premises imposed by any governmental or quasi-governmental
authority and all taxes specifically imposed in lieu of any such taxes, but
excluding any inheritance, estate, succession, transfer, gift, franchise,
corporation, income, rental or profit tax or capital levy imposed on Landlord
("Taxes"). If due to a future change in the method of taxation, any franchise,
income, profit or other tax shall be levied against Landlord in whole or in part
in lieu of any tax which would otherwise constitute one of the foregoing taxes
or charges or if there shall be levied against Landlord a tax or license fee
measured by gross rents, such franchise, income, profit or other tax or license
fee shall be deemed to be a real estate tax for the purposes hereof. The taxes
described in this Section 6(b)(i) shall also include all of Landlord's expenses,
including, but not limited to, attorney's fees, incurred by Landlord in any
effort to minimize such taxes, whether by contesting proposed increases in
assessments or by any other means or procedures appropriate in the
circumstances; provided that Landlord and Tenant shall agree to the procedures
to be taken prior to Landlord taking such procedures. If Landlord secures an
abatement or refund of any Taxes, Landlord shall pass such abatement through to
the Tenant as a credit to be applied against rent next becoming due, or if no
further rent is due by Tenant, by cash payment from Landlord to Tenant.

            (ii) Except as otherwise set forth in this Lease, all costs, charges
and expenses (not directly reimbursed by insurance proceeds) which are
attributable to the ownership, operation, maintenance and repair of the
Premises, including, but not limited to, reasonable management fees that fall

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within industry standards for the Boulder area, building supplies, window
cleaning services, normal maintenance and repair of the Premises, including but
not limited to, heating and air conditioning systems, electrical and plumbing
systems, elevator system, landscaping, snow removal, Parking Lot repair and
maintenance, insurance (including boiler and machinery, loss of rent, accidental
and direct physical loss, all risk, public liability and other insurance as
provided in Section 20) and labor costs incurred in the operation or maintenance
of the Premises. Except as provided in Section 6(a)(iii), and except for repairs
and replacements for which Landlord is reimbursed from insurance proceeds, all
repairs and replacements shall either be made by Tenant directly or shall be
made by Landlord at Tenant's expense as an Operating Cost.

      Operating Costs shall be based upon competitive charges for similar
services and materials that are available in the general vicinity of the
Premises. Operating Costs shall be reduced by the proceeds of insurance or
eminent domain awards of settlement received by Landlord with respect to items
of Operating Cost (or the amount of any proceeds or awards which would have been
received if Landlord had carried the insurance required by this Lease or
diligently pursued its rights, as the case may be) or recoveries from warranty
claims. Landlord shall not be permitted to recover more than the actual
out-of-pocket cost incurred by Landlord on a non-profit basis for the Operating
Cost. The Operating Cost shall be determined on a "cash basis" and costs which
may be paid in installments without finance charges shall be paid in
installments. Promptly upon receipt thereof, Landlord shall pay Tenant any
refund or recovery made with respect to any Operating Cost previously paid by
Tenant.

            (iii) The following expenses and costs shall not be included within
the "Operating Costs" for the Premises: Costs incurred in connection with the
original construction of the Premises or in connection with any major change in
the Premises; depreciation, interest and principal payments on mortgages and
other debt costs, if any; costs of correcting patent and/or latent defects in,
or design errors relating to the design, or construction of the Building located
on the Premises; costs for which the Landlord is reimbursed by insurance
proceeds; costs associated with the operation of the business of the Landlord as
a separate entity, as the same are distinguished from the cost of operating the
Premises; the wages and benefits of any executive or other employee at or above
the level of building manager, or any employee who does not devote substantially
all of his or her employee time to the Premises unless such wages and benefits
are prorated to reflect time spent on operating and managing the Premises;
fines, penalties and interests; tax penalties incurred as a result of the
Landlord's negligence, inability, or unwillingness to make payments when due;
any expense resulting from the negligence of, or any violation of law by,
Landlord or its agents, contractors, employees or invitees; and Landlord's
general overhead and general administrative expenses. Except where the need for
repair or replacement results from the negligence of Tenant or its agents,
employees or invitees, or as a result of the operations of Tenant's business,
Landlord shall, upon reasonable notice from Tenant and at its expense and
without reimbursement by Tenant (other than from insurance proceeds from
insurance provided by Tenant), perform all replacement of, and structural
repairs to the structural portions of the Premises as are necessary to keep the
same in first class order, condition and repair, reasonable wear and tear
excepted. For purposes of this Lease, "structural portions" of the Premises
shall mean the foundation, supporting members of the roof, floor slabs, exterior
walls, structural girders and columns, load-bearing walls and columns. (It is
acknowledged that movement of floor slabs is normal and not generally repaired
in first class industrial buildings, unless the movement is excessive.)

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      (c) Tenant shall have the right to inspect all documents reflecting any
part of the Operating Costs and the calculations of any amount payable under
Section 6(a) of this Lease, and Landlord shall provide written receipts and
accounting records supporting its itemized statements and calculations of
Operating Costs and the amounts due under Section 6(a) once each year upon
request by Tenant. If Tenant wishes to dispute the determination of Operating
Costs under Section 6(a) or the calculation of any amount payable under Section
6(a), Tenant shall give Landlord written notice of such dispute within ninety
(90) days after receipt of notice from Landlord of the matter giving rise to the
dispute. If Tenant does not provide Landlord such notice within such time,
Tenant shall have waived its right to dispute such determination or calculation.
Promptly after the giving of such written notice, Tenant shall cause to be made
a complete audit of Landlord's records relating to the matter in dispute by a
nationally recognized firm of independent certified public accountants mutually
agreed upon by Landlord and Tenant. The cost of such audit shall be borne by
Tenant unless such audit discloses an error which overstated Operating Cost by
more than two percent (2%) of the amount determined by the audit, in which event
Landlord shall bear the cost of such audit. If such audit reveals that the
amount previously determined by Landlord was incorrect, a correction shall be
made and either Landlord shall promptly return to Tenant any overpayment or
Tenant shall promptly pay to Landlord any underpayment which was based on such
incorrect amount. Notwithstanding the pendency of any dispute hereunder, Tenant
shall make payments based upon Landlord's determination or calculation until
such determination or calculation has been established hereunder to be
incorrect.

      Section 7. UTILITIES & CLEANING.

      Tenant shall directly contract for and pay for all utilities serving the
Premises, including, but not limited to, gas, steam, water, fuel oil,
electricity, sewer charges, telephone and communications systems and the like;
and Landlord shall not be responsible for or involved in the payment of or the
contracting for any said utilities. Likewise, Tenant shall directly contract for
and pay for janitorial services and interior window cleaning and Landlord shall
not be responsible for or involved in the payment of or contracting for any of
said services.

      Section 8. TAXES

      Tenant shall pay before delinquency any and all taxes, assessments,
license taxes and other charges levied, assessed or imposed and which become
payable during the Term of this Lease upon Tenant's operations at, occupancy of,
or conduct of business at the Premises or upon equipment, furniture, appliances,
trade fixtures and other personal property of any kind installed or located at
the Premises; provided, however, Tenant may pay such amounts after delinquency
to the extent that such delay is necessary to Tenant's good faith and diligent
contest of such amounts, but only so long as there is no risk of Tenant having
any of its assets or Landlord's assets foreclosed upon or seized by the taxing
authority.

      Section 9. QUIET ENJOYMENT

      Landlord covenants and agrees with Tenant that upon Tenant paying the Base
Rent and additional rent hereunder and observing and performing all the terms,
covenants and conditions of this Lease on Tenant's part to be observed and
performed, Tenant may peaceably and quietly enjoy the Premises subject,

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nevertheless, to the terms and conditions of this Lease and the matters shown as
items 8-20 on Schedule B to the Landlord's title policy, a copy of which is
attached hereto as Exhibit D.

      Section 10. PREPARATION OF PREMISES

      (a) Landlord shall Substantially Complete (as defined in Section 30) the
work in the Premises required to be done by Landlord as specified in Exhibit B
attached hereto ("Landlord's Work"). All Landlord's Work shall be performed in a
good and workmanlike manner with new, first quality materials in compliance with
all laws, codes and all regulations. Landlord will obtain a fifteen (15) year
warranty on the roof naming the Landlord and Tenant on all related warranties.
Landlord represents that the Premises will be in compliance with the ADA. If
Landlord's Work is not performed as herein required, or if such work or the
Premises in not in compliance with all laws, codes or other regulations,
Landlord shall perform the necessary remedial work at its sole cost and expense.
Landlord and Tenant agree that Wyatt Construction Company shall be the general
contractor (the "Contractor") and RVP Architecture shall be the architect (the
"Architect") used by the parties for the purposes of performing Landlord's Work
subject to change in the event of failure or inability to perform. Landlord
shall exercise due diligence in pursuit of completing Landlord's Work. Landlord
shall permit Tenant to have access to the Premises prior to the commencement of
the Lease for purposes of inspecting Landlord's Work or with Contractor's
consent, for performing work in the Premises. Landlord agrees to proceed with
due diligence to complete any portion of Landlord's Work that shall not have
been completed as of the date of Substantial Completion of the foregoing by not
later than thirty (30) days after the date of Substantial Completion (excluding
seasonal landscaping, which shall be completed promptly as soon as the season
permits).

      (b) Except for minor changes to comply with applicable law or to correct
any mistakes in the plans or specifications, no change orders from the plans and
specifications set forth on Exhibit B shall be permitted, unless duly authorized
representatives of both Tenant and Landlord shall agree to the change order in
writing. Each change order shall set forth the changes in the plans and
specifications and an estimate of the increase in the price to be charged by the
Contractor and any delay in the construction schedule. Thereafter, within thirty
(30) days after receipt of documentation showing the amount charged to Landlord
by the Contractor for the change order, Tenant shall reimburse Landlord for such
amount, unless such amount is more than 10% more than the estimate set forth in
the change order, in which event Tenant shall pay Landlord the amount of the
estimate plus 10% of the amount of the estimate.

      (c) Landlord acknowledges that it is a material provision of this Lease
that Landlord deliver the Premises to Tenant by the date Landlord sets forth in
its Official Estimate (defined below) and in the condition provided herein. An
Initial Estimate date shall be provided by Landlord to Tenant within fifteen
(15) days after the appropriate building permit has been issued by the
government authorities. In no case shall the Initial Estimate date be later than
the Substantially Complete date set forth in Section 30 herein. In recognition
thereof, Landlord agrees to provide Tenant with preliminary written statements
signed by both Landlord and the Contractor on the first day of each month, from
and after the commencement of construction until the Commencement Date of the
Lease, detailing the status of Landlord's Work compared to the Initial Estimate
date and/or the Official Estimate date and the estimated date of substantial
completion of Landlord's Work. Landlord's preliminary estimates may change the
Initial Estimate date of substantial completion of Landlord's work (reference

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Section 30); provided that once Landlord's estimate of such date falls within
ninety (90) days of the date of the Substantial Completion date, it shall be
referred to as the "Official Estimate". In the event that the Commencement Date
occurs on or after that date which is fifteen (15) days plus any days of delay
caused by change orders or Tenant's work on the Premises after the Commencement
Date set forth in the Official Estimate, Tenant shall be entitled to a rent
reduction equal to $750.00 times the number of days after the fifteenth day plus
any days of delay caused by change orders or Tenant's work on the Premises after
the Commencement Date set forth in the Official Estimate, but before the actual
Commencement Date.

      Section 11. ACCEPTANCE OF PREMISES

      Taking possession of the Premises by Tenant shall be conclusive evidence
as against Tenant that the Premises were in good and satisfactory condition when
Possession was taken subject to correction (by Landlord at its expense) of punch
list or other defective items disclosed to Landlord prior to taking of
possession of the Premises by Tenant, defects not reasonably discoverable prior
to taking possession and disclosed to Landlord within a reasonable period of
time after discovery of same by Tenant, but no later ninety (90) days after
taking possession of the Premises, and latent defects disclosed to Landlord
within a reasonable time after discovery of same by Tenant.

      Section 12. ACCESS TO PREMISES

      Landlord and Tenant acknowledge that Tenant shall be performing
confidential work within the Premises, which confidential work shall not be
accessible to Landlord. Accordingly, Landlord agrees that it will cooperate with
Tenant so as to preserve the confidentiality of Tenant's work (and such
cooperation shall include, but not be limited to, if requested by Tenant, the
execution of confidentiality agreements by Landlord and its agents, assigns,
employees and contractors, and other reasonable measures to preserve Tenant's
confidentiality). Unless Tenant shall consent to a shorter time, Landlord will
provide at least twenty-four (24) hours advance notice to Tenant prior to
entering the Building, will schedule with Tenant the time and place of all entry
by Landlord or its agents, assigns, employees or contractors, and will only
enter upon the Building with a duly-authorized representative of Tenant, except
in the event of an emergency. Landlord agrees to use its best efforts not to
interfere unreasonably with the Tenant or the Tenant's business in the course of
exercising its rights under this paragraph.

       Section 13. ALTERATIONS BY TENANT

      (a) Other than interior, non-structural alterations, for which Landlord's
consent is not required, Tenant shall make no alterations, decorations,
installations, additions or improvements in or to the Premises without first
obtaining the written consent of Landlord. Tenant understands that Landlord's
consent will be conditioned on Tenant's compliance with Landlord's requirements
as in effect at the time permission is requested, which requirements will
include, but not be limited to Landlord's approval of plans, specifications,
contractors, insurance, and hours of construction. Prior to the commencement of
any work in or to the Premises by Tenant's contractor, Tenant shall comply with
all applicable laws (for example, by obtaining a building permit if required),
and Tenant shall on request deliver to Landlord certificates issued by
applicable insurance companies evidencing that workmen's compensation and public
liability insurance and property damage insurance, all in amounts and with
companies, and on forms reasonably satisfactory to Landlord,

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are in force and effect and maintained by all contractors and subcontractors
engaged by Tenant to perform such work. Each such certificate shall provide that
it may not be cancelled without ten days' prior written notice to Landlord.

      (b) All articles of personal property, and all movable business and trade
fixtures, machinery and equipment, cabinetwork, furniture and movable partitions
owned or installed by Tenant at its sole expense (and with respect to which no
credit or allowance was granted to Tenant by Landlord) in the Premises shall
remain the property of Tenant and may be removed by Tenant at any time, provided
that Tenant, at its expense, shall repair any damage to the Premises caused by
such removal. All alterations, decorations, installations, additions or
improvements in or to the Premises other than those specified in the first
sentence of this Section 13(b) shall, upon the completion thereof, become the
property of Landlord and shall be surrendered to Landlord upon the expiration or
other termination of the Term of this Lease. Landlord may elect to require
Tenant to remove all or any part of the property described in the first sentence
of this Section 13(b) at the expiration or other termination of the Term of this
Lease, in which event such removal shall be done at Tenant's expense, and Tenant
shall, at its expense, repair any damage to the Premises caused by such removal.

      (c) Tenant shall be solely responsible for the consequences of Tenant's
repairs and alterations on the Premises' structure and on the operation of its
systems, such as heating, air conditioning, ventilating, electrical and
plumbing, whether or not Tenant had received Landlord's consent to such repairs
or alterations pursuant to this Section 13.

      Section 14. MAINTENANCE AND REPAIRS

      (a) Except for the maintenance, repairs and replacements Landlord is
required to make pursuant to Section 13(b) of this Lease, and except for items
expressly excluded from Operating Costs under Section 6(b)(iii), Tenant shall
take good care of the Premises and the fixtures and improvements therein, and,
at its sole cost and expense, make repairs, restorations or replacements as and
when needed to keep the Premises in first class order, condition, and repair,
reasonable wear and tear excepted. If Tenant fails, after notice to Tenant and
the lapse of applicable grace periods in accordance with Section 31(b) of this
Lease, to make any repairs, restorations or replacements required by this Lease,
Landlord may (but without any obligation to do so) make such repairs,
restorations, or replacements at the reasonable expense of Tenant and such
expense shall be due within thirty (30) days of receipt by Tenant of written
notice by Landlord, as additional rent. Tenant shall comply with all provisions
of Section 13 and Section 15 of this Lease in connection with such repairs,
restorations and replacements.

      (b) Subject to Section 14(c), (d) and (e) hereof, and subject to Tenant's
reimbursement of Landlord as provided in Section 6(b) hereunder, Landlord shall
act as property manager for the Premises and, in such capacity, shall be
responsible for the operation, maintenance and repair of the Premises, including
but not limited to: Building maintenance, exterior window cleaning, normal
maintenance and repair of the Premises (including heating and air conditioning
systems, electrical and plumbing systems, landscaping, roof, roof membrane,
elevator system, utility systems, Parking Lot, and snow removal) and security
outside of the Building. In addition, Landlord shall make the structural repairs
and replacements to the structural portion of the Premises that Landlord is
required to make, at Landlord's cost and expense, without reimbursement from
Tenant, pursuant to Section 6(b)(iii) of this Lease.

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      (c) Landlord agrees not to assign its responsibilities as property manager
of the Premises to any other person or entity without first providing written
notice to Tenant and obtaining Tenant's written consent to such assignment.

      (d) Landlord agrees, by not later than 45 days prior to the Commencement
Date, to provide Tenant's Facilities Manager with a detailed property management
plan for the Premises, including proposed staffing levels and standards of
management and maintenance of the Premises. Tenant shall respond with its
comments or approval of such plan within thirty (30) days of receipt of the
management plan and to any revised submittal within ten (10) days of its receipt
of the same. Landlord and Tenant shall discuss who Landlord shall hire or
contract with as major service providers for the Premises. Landlord shall have
yearly inspections of the roof as required by the terms of the roof warranty and
Landlord and Tenant shall cooperate in the enforcement of the roof warranty.
Landlord shall advise Tenant in advance of any repair or maintenance cost
believed to be in excess of $10,000. In the event Landlord or Tenant shall
disagree about such plans, the need for such maintenance or repairs, or whom to
hire as service providers, then Landlord and Tenant shall agree to a third party
property manager, which third party property manager shall informally arbitrate
such disputes.

      (e) Except as provided elsewhere in this Lease to the contrary, there
shall be no allowance to Tenant for a diminution of rental value and no
liability on the part of Landlord, by reason of inconvenience, annoyance or
injury to, or interruption of business, arising from Landlord, Tenant or others
making any repairs, restorations, replacements, alterations, additions or
improvements in or to any portion of the Premises, or in or to fixtures,
appurtenances or equipment thereof; provided that such repairs, restorations,
etc. do not prevent Tenant from operating in the Premises as anticipated
hereunder for more than twenty-four hours. In such case, Rent hereunder shall be
abated in proportion to the untenantable space in the Premises. Notwithstanding
the provisions of Section 12, Section 14 or Section 21 or any other provision of
this Lease to the contrary, in exercising its rights pursuant to this Lease,
Landlord shall not unreasonably interfere with the access to the Premises or
Tenant's business operations therein.

      Section 15. MECHANIC'S LIENS

      (a) Tenant shall, at Tenant's option, pay or cause to be paid or provide
bond for all costs for work done by it or caused to be done by it on the
Premises of a character which will or may result in liens on Landlord's interest
therein and Tenant will keep the Premises free and clear of all mechanic's
liens, and other liens on account of work done for Tenant or persons claiming
under it. Tenant shall indemnify and hold Landlord harmless against any
liability, loss, damage, costs or expenses, including reasonable attorney's
fees, on account of any claims of any nature whatsoever, including claims of
liens of laborers or materialmen or others for work performed for, or materials
or supplies furnished to Tenant or persons claiming under Tenant.

      (b) Should any liens be filed or recorded against the Premises or any
action affecting the title thereto be commenced due to Tenant's contracts with
third parties, Tenant shall give Landlord written notice thereof. Tenant shall
thereafter cause such liens to be removed of record within ten days after the
filing of the liens. If a final judgment establishing the validity or existence
of a lien for any amount is entered, Tenant shall pay and satisfy the same at
once. If Tenant shall be in default in paying any charge for which a mechanic's

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lien or suit to foreclose the lien has been recorded or filed, Landlord may (but
without being required to do so) pay such lien or judgment and any costs, and
the amount so paid, together with reasonable attorney's fees incurred in
connection therewith, shall be immediately due from Tenant to Landlord with
interest at the Default Rate from the dates of Landlord's payments. Landlord
shall be responsible for the payment for all work (including Landlord's Work),
and the removal of all liens of record relating to work of Landlord occurring
prior to the Commencement Date, or, thereafter, work performed by Landlord or
its contractors.

      (c) At least five days prior to the commencement of any work permitted to
be done by persons requested by Tenant on the Premises in excess of $10,000.00,
Tenant shall notify Landlord of the proposed work and the names and addresses of
the persons supplying labor and materials for the proposed work so that Landlord
may avail itself of the provisions of statutes such as Section 38-22-105(2) of
Colorado Revised Statutes (1973, as amended). During any such work on the
Premises, Landlord and its representatives shall have the right to go upon and
inspect the Premises at all reasonable times, and shall have the right to post
and keep posted thereon notices such as those provided for by Section
38-22-105(2).

      Section 16. CASUALTY

      (a) If the Building or the Parking Lot or means of access or ingress to
the Premises shall be so damaged by fire or other casualty as to render the
Premises untenantable, and if such damage shall be so great that an architect
selected by Landlord and agreed to by Tenant shall certify in writing to
Landlord and Tenant that the Premises with the exercise of reasonable diligence,
but without the payment of overtime or other premiums cannot be made tenantable
within 90 days from the happening of the fire or other casualty, or if the
damage shall be such that Landlord's architect shall certify that the Premises
can be made tenantable within the 90-day period from the happening of the fire
or other casualty, but insurance proceeds are not made available to Landlord for
repair of such damage, then Landlord or Tenant may terminate this Lease. If
neither Landlord nor Tenant terminates this Lease as set forth above, then,
except as hereinafter provided, Landlord shall with reasonable promptness,
repair the damage so done except that Landlord shall not be required to repair,
replace or restore any personal property of Tenant specified in the first
sentence of Section 13(b). Until such repair is substantially completed, the
Base Rent shall be abated in proportion to the part of the Premises which is
unusable by Tenant in the reasonable conduct of its business or profession.
There shall be no abatement of Base Rent by reason of any portion of the
Premises being unusable for a period of one day or less, unless covered by
Landlord's loss of rent insurance. If the damage is due to the fault or
negligence of Tenant or Tenant's employees, agents or invitees, there shall be
no abatement of Base Rent, unless covered by Landlord's loss of rent insurance.

      (b) If the Premises shall be damaged by fire or other casualty, but not so
as to render the entire Building untenantable, Landlord shall cause the damage
to be repaired with reasonable promptness and, if not repaired sufficiently that
the entire Premises is tenantable within one day, there shall be an abatement of
Base Rent and all other amounts due under this Lease in proportion to the
Rentable Square Footage of the Premises rendered untenantable. If the fire or
other casualty causing damage to the Premises shall have been caused by the
negligence of Tenant, or Tenant's employees, agents or invitees, such damage
shall be repaired by Landlord and the amount paid for such repair shall be due
from Tenant to Landlord with interest at the Default Rate from the

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dates of Landlord's payments, unless Landlord is paid for such