COMMON STOCK PURCHASE WARRANT

THIS WARRANT AND THE SHARES OF COMMON STOCK ISSUABLE UPON EXERCISE OF THIS WARRANT HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY STATE SECURITIES LAWS. THIS WARRANT AND THE COMMON STOCK ISSUABLE UPON EXERCISE OF THIS WARRANT MAY NOT BE SOLD, OFFERED FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF (A) AN EFFECTIVE REGISTRATION STATEMENT AS TO THIS WARRANT UNDER SAID ACT AND ANY APPLICABLE STATE SECURITIES LAWS OR (B) AN EXEMPTION FROM SUCH REGISTRATION REQUIREMENTS.

Right to Purchase up to 100,000 Shares of Common Stock of
STEN CORPORATION
(subject to adjustment as provided herein)

COMMON STOCK PURCHASE WARRANT

No.____

Issue Date:  October 31, 2008

STEN CORPORATION, a corporation organized under the laws of the State of Minnesota (the “ Company ”), hereby certifies that, for value received, VALENS U.S. SPV I, LLC, or permitted transferees or assigns (the “ Holder ”), is entitled, subject to the terms set forth below, to purchase from the Company (as defined herein) from and after the Issue Date of this Warrant and at any time or from time to time before 5:00 p.m., New York time, through the close of business October 31, 2013 (the “ Expiration Date ”), up to 100,000 fully paid and non-assessable shares of Common Stock (as hereinafter defined), $0.01 par value per share, at the applicable Exercise Price per share (as defined below).  The number and character of such shares of Common Stock and the applicable Exercise Price per share are subject to adjustment as provided herein.

As used herein the following terms, unless the context otherwise requires, have the following respective meanings:

(a)

“Common Stock ” means (i) the Company’s Common Stock, par value $0.01 per share; and (ii) any other securities into which or for which any of the securities described in the preceding clause (i) may be converted or exchanged pursuant to a plan of recapitalization, reorganization, merger, sale of assets or otherwise.

(b)

“ Company ” means STEN Corporation and any person or entity which shall succeed, or assume the obligations of, STEN Corporation hereunder.

(c)

“ Exercise Price ” means a price of $0.01 per share.

(d)

“ Other Securities ” means any stock (other than Common Stock), including, but not limited to, the Closing Shares (as defined in the Security Agreement) and other securities of the Company or any other person (corporate or otherwise) which the Holder at any time shall be entitled to receive, or shall have received, on the exercise of this Warrant, in lieu of or in addition to Common Stock, or which at any time shall be issuable or shall have been issued in exchange for or in replacement of Common Stock or Other Securities pursuant to Section 4 or otherwise.

(e)

“ Security Agreement ” means the Security Agreement dated as of the date hereof among the Company, various Subsidiaries of the Company party thereto, the Holder, the other Lenders (as defined therein) from time to time party thereto and LV Administrative Services, Inc., as administrative and collateral agent for the Lenders, as amended, modified, restated and/or supplemented from time to time.

1.

Exercise of Warrant .

1.1

Number of Shares Issuable upon Exercise .  From and after the date hereof through and including the Expiration Date, the Holder shall be entitled to receive, upon proper exercise of this Warrant in whole or in part, by delivery of an original or fax copy of an exercise notice in the form attached hereto as Exhibit A (the “ Exercise Notice ”) and payment of the Exercise Price (either in cash or securities or on a cashless basis) therefor, shares of Common Stock of the Company, subject to adjustment pursuant to Section 4.

1.2

Fair Market Value .  For purposes hereof, the “Fair Market Value” of a share of Common Stock as of a particular date (the “ Determination Date ”) shall mean:

(a)

If the Company’s Common Stock is traded on the American Stock Exchange or  another national exchange or is quoted on the National or Capital Market of The Nasdaq Stock Market, Inc. (“ Nasdaq ”), then the closing or last sale price, respectively, reported for the last business day immediately preceding the Determination Date.

(b)

If the Company’s Common Stock is not traded on the American Stock Exchange or another national exchange or on the Nasdaq but is traded on the NASD Over the Counter Bulletin Board, then the mean of the average of the closing bid and asked prices reported for the last business day immediately preceding the Determination Date.

(c)

Except as provided in clause (d) below, if the Company’s Common Stock is not publicly traded, then as the Holder and the Company agree or in the absence of agreement by arbitration in accordance with the rules then in effect of the American Arbitration Association, before a single arbitrator to be chosen from a panel of persons qualified by education and training to pass on the matter to be decided.

(d)

If the Determination Date is the date of a liquidation, dissolution or winding up, or any event deemed to be a liquidation, dissolution or winding up pursuant to the Company’s charter, then all amounts to be payable per share to holders of the Common Stock pursuant to the charter in the event of such liquidation, dissolution or winding up, plus all other amounts to be payable per share in respect of the Common Stock in liquidation under the charter, assuming for the purposes of this clause (d) that all of the shares of Common Stock then issuable upon exercise of this Warrant are outstanding at the Determination Date.

1.3

Company Acknowledgment .  The Company will, at the time of the exercise of this Warrant, upon the request of the Holder acknowledge in writing its continuing obligation to afford to the Holder any rights to which the Holder shall continue to be entitled after such exercise in accordance with the provisions of this Warrant.  If the Holder shall fail to make any such request, such failure shall not affect the continuing obligation of the Company to afford to the Holder any such rights.

1.4

Trustee for Warrant Holders .  In the event that a bank or trust company shall have been appointed as trustee for the Holder pursuant to Subsection 3.2, such bank or trust company shall have all the powers and duties of a warrant agent (as hereinafter described) and shall accept, in its own name for the account of the Company or such successor person as may be entitled thereto, all amounts otherwise payable to the Company or such successor, as the case may be, on exercise of this Warrant pursuant to this Section 1.

1.5

Limitation on Sale of Common Stock .  Notwithstanding anything contained herein to the contrary, the Holder shall not be entitled to sell any shares of Common Stock underlying this Warrant, in whole or in part, prior to September 1, 2009 (the “Lock-up Period”).  Notwithstanding the foregoing, the Lock-up Period shall become null and void without any notice to the Company upon the occurrence and during the continuance of an Event of Default (as defined in the Security Agreement).

2.

Procedure for Exercise .

2.1

Delivery of Stock Certificates, Etc., on Exercise .  The Company agrees that the shares of Common Stock purchased upon exercise of this Warrant shall be deemed to be issued to the Holder as the record owner of such shares as of the close of business on the date on which the Exercise Notice is received, this Warrant shall have been surrendered and payment made for such shares in accordance herewith.  As soon as practicable after the exercise of this Warrant in full or in part, and in any event within five (5) business days thereafter, the Company at its expense (including the payment by it of any applicable issue taxes) will cause to be issued in the name of and delivered to the Holder, or as the Holder (upon payment by the Holder of any applicable transfer taxes) may direct in compliance with applicable securities laws, a certificate or certificates for the number of duly and validly issued, fully paid and non-assessable shares of Common Stock (or Other Securities) to which the Holder shall be entitled on such exercise, plus, in lieu of any fractional share to which the Holder would otherwise be entitled, cash equal to such fraction multiplied by the then Fair Market Value of one full share, together with any other stock or other securities and property (including cash, where applicable) to which the Holder is entitled upon such exercise pursuant to Section 1 or otherwise.

2.2

Exercise .

(a)

Payment may be made either (i) in cash by wire transfer of immediately available funds or by certified or official bank check payable to the order of the Company equal to the applicable aggregate Exercise Price, (ii) by delivery of shares of Common Stock and/or Common Stock issuable upon exercise of this Warrant in accordance with the formula set forth in subsection (b) below, or (iii) by a combination of any of the foregoing methods, for the number of shares of Common Stock specified in such Exercise Notice (as such exercise number shall be adjusted to reflect any adjustment in the total number of shares of Common Stock issuable to the Holder per the terms of this Warrant) and the Holder shall thereupon be entitled to receive the number of duly authorized, validly issued, fully-paid and non-assessable shares of Common Stock (or Other Securities) determined as provided herein.

(b)

Notwithstanding any provisions herein to the contrary, if the Fair Market Value of one share of Common Stock is greater than the Exercise Price (at the date of calculation as set forth below), in lieu of exercising this Warrant for cash, the Holder may elect to receive shares equal to the value (as determined below) of this Warrant (or the portion thereof being exercised) by surrender of this Warrant at the principal office of the Company together with the properly endorsed Exercise Notice in which event the Company shall issue to the Holder a number of shares of Common Stock computed using the following formula:

3.

Effect of Reorganization, Etc.; Adjustment of Exercise Price .

3.1

Reorganization, Consolidation, Merger, Etc .  If there occurs any capital reorganization or any reclassification of the Common Stock of the Company, the consolidation or merger of the Company with or into another person (other than a merger or consolidation of the Company in which the Company is the continuing entity and which does not result in any reorganization or reclassification of its outstanding Common Stock) or the sale or conveyance of all or substantially all of the assets of the Company to another person, then, as a condition precedent to any such reorganization, reclassification, consolidation, merger, sale or conveyance, the Holder will be entitled to receive upon surrender of this Warrant to the Company (x) to the extent there are cash proceeds distributed to holders of Common Stock following the consummation of such reorganization, reclassification, consolidation, merger, sale or conveyance, in exchange for such Warrant, cash in an amount equal to the cash proceeds that would have been payable to the Holder had the Holder exercised such Warrant immediately prior to the consummation of such reorganization, reclassification, consolidation, merger, sale or conveyance, less the aggregate Exercise Price payable upon exercise of this Warrant, and (y) to the extent that the Holder would be entitled to receive Common stock (or Other Securities) (in addition to or in lieu of cash in connection with any such reorganization, reclassification, consolidation, merger, sale or conveyance),