Exhibit 10.25

LEASE

Between

LONGBARREL PROPERTY LIMITED PARTNERSHIP

and

SPECTRALINK CORPORATION

September         , 2005

PARTICULARS

DATED

PARTIES

OPERATIVE PROVISIONS

1                                                     Definitions and interpretation

1.1                                            Unless the contrary intention appears the following definitions apply:

1

2

3

4

5

1.2                                            Any obligation on a party to this Lease to do any act includes an obligation to procure that it is done.

1.3                                            Where the Tenant is placed under a restriction in this Lease the restriction includes the obligation on the Tenant not to permit or allow the infringement of the restriction by any person under the Tenant’s control.

1.4                                            References to liability include where the context allows claims demands proceedings damages losses costs and expenses.

1.5                                            The clause and paragraph headings in this Lease are for ease of reference only and are not to be taken into account in the construction or interpretation of any provision to which they refer.

1.6                                            Unless the contrary intention appears references:

1.6.1                                                             to numbered clauses and schedules are references to the relevant clause in or schedule to this Lease; and

1.6.2                                                             to a numbered paragraph in any schedule are references to the relevant paragraph in that schedule.

1.7                                            Words in this Lease denoting the singular include the plural meaning and vice versa.

1.8                                            Except for the Town and Country Planning (Use Classes) Order 1987 references in this Lease to any statutes or statutory instruments include any statute or statutory

6

                                                          instrument amending consolidating or replacing them respectively from time to time in force and references to a statute include statutory instruments and regulations made pursuant to it.

1.9                                            Words in this Lease importing one gender include both other genders and may be used interchangeably and words denoting natural persons where the context allows include corporations and vice versa.

1.10                                      For the purposes of this Lease two companies are members of the same group if one is the subsidiary of the other or both are subsidiaries of a third company “subsidiary” having the meaning given to it in section 736 of the Companies Act 1985.

1.11                                      In this Lease unless there be something in the subject or context inconsistent therewith where there are two or more persons included in the expression “the Tenant” or “the Guarantor” then covenants made by them shall be covenants by them jointly and severally.

2                                                     The Landlord at the request of the Guarantor hereby demises unto the Tenant the Property together with the rights set out in Schedule 4 except and reserved to the Landlord and all others so authorised the rights set out in Schedule 1 for the Term and subject to the Encumbrances the Tenant paying during the Term:

2.1                                            the yearly rent of £95,568 by equal quarterly payments in advance on the usual quarter days in every year the first (or a proportionate part) of such payments in respect of the period commencing on the Rent Commencement Date and ending on the day preceding the following quarter day to be made on the Rent Commencement Date; and

2.2                                            as additional rent:

2.2.1                                                             the Service Charge commencing on the Term Commencement Date;

2.2.2                                                             the costs incurred by the Landlord under clause 4.2 commencing on the Term Commencement Date;

2.2.3                                                             Interest payable by the Tenant under the terms of this Lease; and

2.2.4                                                             such value added tax as may be chargeable on the rent and other additional rents reserved by this Lease.

7

3                                                     The Tenant covenants with the Landlord during the Term and any statutory extension of the tenancy created by this Lease as follows:

3.1.1                                                             To pay the yearly rent at the times and in the manner required in clause 2 free from any deductions and rights of set-off (except where required by law) (legal or equitable) and by means of standing order to the Tenant’s bankers.

3.1.2                                                             To pay the additional rents reserved by this Lease at the times and in the manner specified.

3.2

3.2.1                                                             To pay Interest on so much of the yearly rent as remains unpaid after it has become due and on the additional rents and other monies payable under this Lease as remain unpaid 7 days after they have become due from the date that they became due until payment is made to the Landlord.

3.2.2                                                             To pay Interest under clause 3.2.1 for any period during which the Landlord properly refuses to accept the tender of payment because of an unremedied breach of covenant by the Tenant.

3.3

3.3.1                                                             To pay Outgoings.

3.3.2                                                             To pay all value added tax (or any tax of a similar nature that may be substituted for it or levied in addition to it) on any sums of money chargeable thereto which shall be due from the Tenant by virtue of the provisions of this Lease and to indemnify the Landlord against any liability to pay value added tax on any such sums insofar as the same may be irrecoverable by the Landlord.

3.3.3                                                             If the Property is damaged by any Insured Risk, the Tenant will pay to the Landlord within 14 days of written demand the amount of any uninsured excess to which the insurance cover of the Landlord is subject.

3.3.4                                                             The Tenant will pay the cost of the revaluation of the Property for insurance purposes but not more than once in any two year period.

3.3.5                                                             To refund to the Landlord within 14 days of written demand (where Outgoings relate to the whole or part of the Building or other property including the Property) a fair and proper proportion of the

8

                                                                                    Outgoings attributable to the Property, such proportion to be conclusively determined by the Landlord or the Landlord’s surveyor (in each case acting reasonably and impartially).

3.3.6                                                             To pay for all gas and electricity consumed on the Property, all charges for meters, and all standing charges.

3.4                                            At all times during the Term to repair, maintain and clean the Property and to keep the Property in good and substantial repair and condition and maintained (except in respect of damage caused by an Insured Risk or Inherent Defect) and to yield up the same at the expiration or sooner determination of the Term or at such later time as the Landlord recovers possession of the Property from the Tenant repaired and kept in accordance with the Tenant’s covenants in this Lease and if so required by the Landlord to remove from the Property all the Tenant’s belongings that is to say trade fixtures and fittings  and all notices notice boards and signs bearing the name of or otherwise relating to the Tenant (including in this context any persons deriving title to the Property under the Tenant) or its business and to make good to the reasonable satisfaction of the Landlord all damage to the Property and the Building resulting from the removal of the Tenant’s belongings from the Property.

3.5                                            Without prejudice to the generality of the foregoing covenant:

3.5.1                                                             In the last three months of the Term (however it may terminate) to paint polish paper or otherwise properly to treat as the case may be all the inside of the Property in a workmanlike manner and in every case with materials of good quality.

3.5.2                                                             Not without the consent of the Landlord to alter, cover up or change any part of the architectural decorations or the external colour of the Property.

3.5.3                                                             To unstop cleanse repair and maintain and so to keep all Conduits exclusively serving the Property and belonging to or forming part of the Property.

3.5.4                                                             To repair or replace if beyond repair forthwith by new articles of similar kind and quality any fixtures fittings or plant or equipment (other than tenant’s or trade fixtures and fittings) upon or in the Property which shall become in need of repair or replacement.

9

3.5.5                                                             To keep the Property properly cleansed and to clean the inside of all windows at least once in every 3 months.

3.6

3.6.1                                                             To permit the Landlord their agents with or without others and appliances at all reasonable hours during the Term upon not less than 48 hours prior written notice (except in case of emergency) to enter the Property to view the state and condition thereof and to give or leave on the Property notice in writing to the Tenant of all defects want of repair and breaches of covenant for which the Tenant is responsible and within two months after every such notice or sooner in an emergency to commence to repair and to make good the same according to such notice to the reasonable satisfaction of the Landlord’s surveyor; and

3.6.2                                                             if the Tenant shall fail within two months days of such notice or immediately in case of emergency to commence and then to diligently and expeditiously comply with such notice it shall be lawful (but without prejudice to the right of re-entry and forfeiture hereinafter contained) for the Landlord its agents and others to enter upon the Property and to carry out or cause to be carried out any of the works referred to in such notice and all costs and expenses properly incurred thereby together with Interest from the date of expenditure by the Landlord shall be paid by the Tenant to the Landlord within 14 days of written demand.

3.7                                            To permit the Landlord its agents or surveyors with or without others and appliances at all reasonable times upon not less than 48 hours prior written notice (except in the case of emergency) during the Term:

3.7.1                                                             to enter the Property to take schedules or inventories of the fixtures fittings plant and machinery belonging to the Landlord or to be yielded up at the expiration or sooner determination of the Term;

3.7.2                                                             to carry out any repairs or other work which the Landlord must or may carry out under the provisions of this Lease upon or to the Property or the Building or to cleanse or empty or renew the Conduits belonging to the same all damage occasioned thereby to the Property being made good as soon as reasonably possible and in a good and workmanlike manner; or

10

3.7.3                                                             to enter upon the Property with or without other persons to exercise any of the rights granted to the Landlord by this Lease;

PROVIDED ALWAYS THAT the Landlord (or other person entering):

(a)           exercising the right in a proper manner and causing as little nuisance as reasonably practicable;

(b)          making good any damage caused to the Property or any of the Tenant’s fixtures and fittings as soon as reasonably practicable;

(c)           where entry is to carry out works, only exercising the right where the works cannot otherwise be reasonably carried out.

3.8                                            Not to do nor cause to be done nor permit or allow any other person to do the following:

3.8.1                                                             alter remove from add to cut or injure or in any way affect:

3.8.1.1                                             the structure of the Property or any structural part thereof or the exterior of the Property or the appearance of the Property as seen from the exterior;

3.8.1.2                                             the non-structural parts of the Property without the prior written consent of the Landlord (such consent not to be unreasonably withheld or delayed);

3.8.2                                                             suspend from or impose upon any part of the Property or the Building any excessive weight nor install any machine which shall be unduly noisy or cause vibrations or otherwise subject the Property or the Building to any strain beyond that which it is designed to bear;

3.8.3                                                             cause or allow any nuisance to the Landlord or its other tenants of the Building or owners, tenants and occupiers of adjoining and neighbouring properties or use the Property for any illegal or immoral act or purpose;

3.8.4                                                             allow any rubbish to accumulate upon the Property, the Building or the Estate;

3.8.5                                                             anything knowingly whereby any policy of insurance relating to the Property, the Building or any adjacent or nearby property may

11

                                                                                    become void or voidable or whereby the premium thereon may be increased and that the Tenant will comply with the requirements of the insurers of the Property;

3.8.6                                                             overload the lifts, electrical installation or Conduits in the Property and/or the Building;

3.8.7                                                             install or erect any exterior lighting, shade, canopy or awning or other structure in front of, or elsewhere outside, the Property including for the avoidance of doubt the part of the Property shown edged red and coloured yellow on Plan 2.

3.9

3.9.1                                                             Not to place or display on the exterior or the windows of the Property or inside the Property so as to be visible from the exterior of the Property any name writing notice sign illuminated sign display of lights placard poster sticker or advertisement other than:

3.9.1.1                                             the name of the Tenant signwritten on the entrance doors of the Property in a style and manner approved by the Landlord or the Landlord’s surveyor, such approval not to be unreasonably withheld or delayed; and

3.9.1.2                                             the name of the Tenant and any permitted sub-tenants displayed on the indicator board in the entrance lobby in the Building and the common signage board in the car park outside the Building.

3.9.2                                                             If any name writing notice sign placard poster sticker or advertisement is placed or displayed in breach of these provisions to permit the Landlord to enter the Property and remove such name writing notice sign placard poster sticker or advertisement and to pay to the Landlord within 14 days of written demand the proper expense of so doing.

3.9.3                                                             Not to erect any satellite dish or aerial of any kind in on or about the Property without the Landlord’s prior written consent which is not to be unreasonably withheld or delayed.

3.10

3.10.1                                                       At the Tenant’s own expense to execute all works provide and maintain all arrangements and comply with the requirements of every enactment (which expression in this Lease includes any act of

12

                                                                                    parliament already or hereafter to be passed any statutory instrument notice direction order regulation bylaw rule and condition already or hereafter to be made under in pursuance of or deriving effect from any such act) of parliament any government department local authority or other public authority or duly authorised officer or court of competent jurisdiction so far as they relate to or affect the Property or the Tenant thereof or the user thereof or the employment therein of any person or the use therein of any machine by the Tenant.

3.10.2                                                       To indemnify the Landlord against all reasonable and proper costs charges and expenses of or incidental to the matters aforesaid and not to do or omit or suffer to be done or omitted any act or thing by reason of which the Landlord may under any enactment incur or have imposed upon them or become liable to pay any penalty damages compensation costs charges or expenses.

3.10.3                                                       To pay to the Landlord within 14 days of written demand all proper and reasonable costs charges and expenses (including surveyor’s architect’s and other professional adviser’s fees) incurred by the Landlord of or incidental to executing all works providing and maintaining all arrangements and complying with the requirements of every enactment or direction as aforesaid so far as the same relate to any property capable of being used or enjoyed by the Tenant in common or jointly with any other person or persons or the user thereof.

3.11                                      To give full particulars to the Landlord as soon as possible of any permission notice order or proposal for a notice or order relevant to the Property or the Building or to the use or condition thereof or otherwise concerning the Tenant made given or issued to the Tenant or the occupier of the Property by any lawful authority and if so reasonably required to produce such document to the Landlord and then as soon as reasonably practicable to take all reasonable or necessary steps to comply therewith and also at the request and cost of the Landlord to make or join with them in making such reasonable and necessary objections or representations against or in respect of any such notice order or proposal as aforesaid as they shall deem expedient (save where in the reasonable opinion of the Tenant such objections or representations would be materially detrimental to the Tenant’s business interests).

13

3.12

3.12.1                                                       Not to use the Property otherwise than as offices and for purposes ancillary to that use.

3.12.2                                                       Nothing in this Lease implies or is to be treated as a warranty to the effect that the use of the Property for those purposes is in compliance with the Planning Acts and all other statutes and regulations relating to Town and Country Planning from time to time in force.

3.13

3.13.1                                                       Not to assign or charge part only of the Property.

3.13.2                                                       Not to assign or charge this Lease without the consent of the Landlord but subject to the operation of the following provisions of this clause 3.13.2 such consent is not to be unreasonably withheld or delayed:

3.13.2.1                                       on an assignment by the Tenant the Landlord may require if it is reasonable and proper to do so a guarantee of the tenant covenants of the assignee from a guarantor who is reasonably and properly acceptable to the Landlord (the operative provisions of which are in the form required in Schedule 5 Part 1); and

3.13.2.2                                       the Landlord may in addition to reasonable and proper grounds withhold its consent to an application by the Tenant for licence to assign this Lease unless (for the purposes of section 19(1A) of the Landlord and Tenant Act 1927) the conditions in this clause 3.13.2.3 are met; that:

(a)                                   at the time of the assignment there are no arrears of rent or other monies due to the Landlord;

(b)                                  if reasonably required at the time of assignment the Tenant enters into an authorised guarantee agreement the operative provisions of which are in the form required in Schedule 5 Part 2; and/or

14

(c)                                   on an assignment by the Tenant to a company which is another member of the same group of companies the ultimate holding company (unless it is the assignee or it would itself be giving an authorised guarantee agreement) enters into a guarantee (the operative provisions of which are in the form required in Schedule 5 Part 1) but if the ultimate holding company would otherwise be released from liability the Landlord may require another substantial member of the group to give the guarantee.

3.13.3                                                       Not to underlet the whole or any part of the Property without the consent of the Landlord (such consent not to be unreasonably withheld or delayed).

3.13.4                                                       On the grant of an underlease to obtain covenants by deed from the underlessee direct with the Landlord in such form as the Landlord may reasonably require that the underlessee will:

3.13.4.1                                       not assign sub-underlet or charge part only of the premises underlet;

3.13.4.2                                       not part with or share possession or occupation of the whole or any part of the premises underlet nor grant rights to third parties over them except by a permitted assignment or sub-underletting;

3.13.4.3                                       not assign, charge or sub-underlet the whole of the premises underlet without obtaining the previous consent of the Landlord under this Lease (such consent not to be unreasonably withheld or delayed); and

3.13.4.4                                       provide for the inclusion in any sub-underleases granted out of the underlease (whether immediate or mediate) of covenants to the same effect as those contained in this clause 3.13.4 and clause 3.13.5.

3.13.5                                                       On the grant of any underlease:

15

3.13.5.1                                       not to reserve or take a premium or fine;

3.13.5.2                                       to reserve a rent which is not less than market rent at the time of the grant of the underlease (assessed in accordance with the principles applied by the court under section 34 of the Landlord and Tenant Act 1954) or (where only part of the Property is underlet) the proportionate part of the market rent of the Property (such proportion to be approved by the Landlord but such approval not to be unreasonably withheld or delayed);

3.13.5.3                                       to include provisions in the underlease to the same effect as those in clause 3.13.2; and

3.13.5.4                                       to include such underlessee covenants as are not inconsistent with or impair the due performance and observance of the covenants of the Tenant in this Lease.

3.13.6                                                       Not to underlet the Property so as to sub-divide the Property into more than two units of occupation.

3.13.7                                                       Not to underlet the whole or any part of the Property except by way of Unsecured Underletting.

3.13.8                                                       Not (except by assignment or underletting permitted under this clause 3.13) to:

3.13.8.1                                       part with or share possession or occupation of the whole or any part of the Property; or

3.13.8.2                                       grant any rights over the Property to third parties.

3.13.9                                                       The preceding provisions of this clause 3.13 do not apply to any parting with possession or occupation or the sharing of occupation or sub-division of the Property to or with any member of a group of companies of which the Tenant is itself a member if:

3.13.9.1                                       the interest in the Property so created is and remains no more than a tenancy at will; and

16

3.13.9.2                                       the possession occupation or sub-division are immediately terminated if the Tenant and the relevant member cease for any reason to be members of the same group of companies.

3.14

3.14.1                                                       Not without the consent of the Landlord (such consent not to be unreasonably withheld or delayed) to vary the terms or waive the benefit of any underlessee covenants or conditions in an underlease of the Property.

3.14.2                                                       Diligently to enforce the underlessee covenants and conditions in any underlease of the Property.

3.14.3                                                       Not without the consent of the Landlord to accept any sum or payment in kind by way of commutation of the rent payable by an underlessee of the Property.

3.14.4                                                       Not to accept the payment of rent from an underlessee of the Property otherwise than by regular quarterly (or more frequent) payments in advance.

3.15                                      To pay to the Landlord all costs charges and expenses (including solicitors’ counsels’ and surveyors’ and other professional costs and fees) properly incurred by the Landlord:

3.15.1                                                       in or in proper contemplation of any proceedings relating to the Property under sections 146 or 147 of the Law of Property Act 1925 or the preparation and service of any notice thereunder (whether or not a notice served under the said section 146 is complied with by the Tenant or the Tenant has been relieved under the provisions of the said Act and notwithstanding that forfeiture is avoided other than by relief granted by the court) and to keep the Landlord fully and effectively indemnified against all costs expenses claims and demands whatsoever in respect of the said proceedings;

3.15.2                                                       in the preparation and service of a schedule of dilapidations at any time during or within 6 months after the termination of this Lease;

3.15.3                                                       in connection with the recovery of arrears of rent due from the Tenant hereunder;

17

3.15.4                                                       in respect of any application for consent or licence required by this Lease whether or not such consent be granted save where such consent shall have been held by a court of law to have been unreasonably withheld or delayed and provided that such costs are reasonably incurred.

3.16                                      In relation to the Planning Acts and legislation of a similar nature and any statutory modification or re-enactment thereof for the time being in force and any order instrument plan regulation permission and directive made or issued or to be made or issued thereunder or deriving validity therefrom:

3.16.1                                                       at all times to comply with the provisions of the Planning Acts and all licences consents and permissions (if any) already or hereafter to be granted or imposed thereunder or under any enactment repealed thereby;

3.16.2                                                       so often as occasion shall require at the Tenant’s own expense to obtain from the proper authority all such licences consents and permissions (if any) as may be required for the carrying out by the Tenant of any operations on or the use of the Property or the institution or continuance by the Tenant thereon of any use thereof which may constitute development within the Planning Acts and not to make or permit any application for planning permission without the written consent of the Landlord such consent not to be unreasonably withheld or delayed in respect of any application by the Tenant pursuant to clause 3.9.3;

3.16.3                                                       unless the Landlord shall otherwise in writing direct to carry out before the expiration or sooner determination of this Lease any works stipulated to be carried out to the Property pursuant to any planning permission applied for by the Tenant whether or not the date by which the planning permission requires such works to be carried out falls during the Term;

3.16.4                                                       when called upon so to do to produce to the Landlord all plans documents and other evidence as they may reasonably require to satisfy itself that the provisions of this covenant have been complied with in all respects;

18

3.16.5                                                       in any case where any planning permission has been granted subject to conditions the Landlord shall be entitled as a condition of giving its consent when otherwise required by this Lease to require the Tenant to provide security for the compliance with the conditions imposed by the permission and the permission shall not be acted upon until such security shall have been provided to the satisfaction of the Landlord;

3.16.6                                                       as soon as reasonably possible to give to the Landlord notice of any order direction proposal or notice under the Planning Acts or relating to any of the matters referred to in this clause 3.16 which is served upon or received by or comes to the notice of the Tenant in connection with or relating to the Property and produce any such