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                                                                    Exhibit 10.1

                   FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT

          This FIRST AMENDMENT TO STOCK PURCHASE AGREEMENT (this "Amendment") is
     dated as of December 28, 2007, by and between Nova Holdings, LLC, a limited
     liability company organized under the laws of the State of Delaware
     ("Seller"), and IDEX Corporation, a corporation organized under the laws of
     the State of Delaware ("Buyer"). Certain terms used but not defined in this
     Amendment have the respective meanings ascribed to such terms in the
     Agreement (as defined below).

          WHEREAS, Seller and Buyer entered into a Stock Purchase Agreement on
     November 13, 2007 (the "Agreement") pursuant to which Seller desires to
     sell to Buyer and Buyer desires to purchase from Seller all the issued and
     outstanding capital stock of Nova Technologies Corporation, a corporation
     organized under the laws of the State of Delaware; and

          WHEREAS, Seller and Buyer desire to amend certain aspects of the
     Agreement as set forth herein.

          NOW THEREFORE, in consideration of the mutual agreements and covenants
     herein contained, and for other good and valuable consideration, the
     receipt and sufficiency of which are hereby acknowledged, the parties
     hereto, intending to be legally bound, agree as follows:

     SECTION 1.1. BASE WORKING CAPITAL. The definition of "Base Working Capital"
set forth in the Agreement is hereby amended and restated in its entirety to
read as follows:

               "(a) "Base Working Capital" means $ 19,200,000."

     SECTION 1.2. CASH. The definition of "Cash" set forth in the Agreement is
hereby amended and restated in its entirety to read as follows:

               "(o) "Cash" means (i) the cash held in deposit accounts,
          including money market accounts (plus an amount equal to the aggregate
          sum of any uncashed checks or EFT transfers to be deposited in such
          deposit accounts and less an amount equal to the aggregate sum of any
          outstanding uncashed checks or EFT transfers drawn on all such deposit
          accounts), of the Company and its Subsidiaries, (ii) cash equivalents
          (including marketable securities) held by the Company and its
          Subsidiaries, (iii) any "restricted" cash or cash deposits held by
          third parties in support of obligations comprising Indebtedness for
          purposes of this Agreement and (iv) any "restricted" cash supporting
          undrawn letters of credit issued in connection with payment,
          performance or other similar bonds."

     SECTION 1.3. PERMITTED ENCUMBRANCES. The definition of "Permitted
Encumbrances" set forth in the Agreement is hereby amended and restated in its
entirety to read as follows:

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               "(eeee)" "Permitted Encumbrances" means (i) liens for Taxes or
          other governmental charges, assessments or levies that are not
          delinquent or are being disputed in good faith, (ii) landlord's,
          mechanic's, carrier's, workmen's, repairmen's or other similar liens
          arising or incurred in the ordinary course of business that do not
          materially detract from the value of the property encumbered thereby,
          but solely to the extent there exists an accrual therefore on the Base
          Balance Sheet or, if incurred after the date of the Base Balance
          Sheet, there exists an accrual therefore in the determination of
          Current Liabilities in connection with the final resolution of Closing
          Net Working Capital pursuant to Section 1.6 hereof, (iii) with respect
          to real property only, minor imperfections of title, conditions,
          easements and reservations of rights, including easements and
          reservations of, or rights of others for, rights of way, sewers,
          electric lines, telegraph and telephone lines and other similar
          purposes, encroachments, covenants and restrictions and (iv) any liens
          or security interests securing Closing Indebtedness to the extent such
          Closing Indebtedness will be repaid by Buyer on the Business Day
          immediately following the Closing pursuant to Section 1.5. Except as
          expressly provided in the preceding clause (iv), any lien for
          Indebtedness as of the Closing will not be deemed to be a Permitted
          Encumbrance."

     SECTION 1.4. ESCROW AMOUNT. The definition of "Escrow Amount" set forth in
the Agreement is hereby amended and restated in its entirety to read as follows:

          "(ww) "Escrow Amount" means $12,500,000."

     SECTION 1.5. ESCROW AGREEMENT. Exhibit A to the Agreement is hereby amended
and restated by substituting Attachment A to this Amendment for the existing
Exhibit A to the Agreement.

     SECTION 1.6. PROMISSORY Note. The Agreement is hereby amended to attach as
Exhibit A-1 thereto the form of promissory note attached hereto as Attachment B.

     SECTION 1.7. CLOSING. Sections 1.4 and 1.5 of the Agreement are amended and
restated in their entirety to read as follows:

          "SECTION 1.4 CLOSING. The Closing shall be held at the offices of
     Goodwin Procter LLP, Exchange Place, Boston, Massachusetts, at, and shall
     be deemed to be effective as of, 4:00 a.m. local time on January 1, 2008 if
     all of the conditions set forth in Article V have been satisfied or waived
     (other than those conditions which by their nature are to be satisfied at
     the Closing). The effective date of the Closing is referred to herein as
     the "Closing Date." On the day immediately prior to the Closing Date, Buyer
     shall deposit with Wells Fargo Bank, N.A. (the "Escrow Agent"), as the
     escrow agent under the Escrow Agreement, the Estimated Purchase Price, by
     wire transfer of immediately available funds to the account or accounts
     previously specified in writing by the Escrow Agent, such amount to be held
     by the Escrow Agent in accordance with the terms of the Escrow Agreement."

          "SECTION 1.5 CERTAIN PAYMENTS AND DELIVERABLES.

               (a) At the Closing, Seller and Buyer will deliver to one another
     letters of direction acknowledging the effective date of the Closing and
     directing that any documents to be delivered to the other party and held in
     escrow be released.


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               (b) At the Closing, (i) Buyer shall deliver to Seller a
     promissory note in the form of Exhibit A-1 in a principal amount equal to
     (A) the Estimated Purchase Price less (B) the Escrow Amount, and (ii)
     Seller shall deliver stock powers duly executed in blank, and permitting
     Buyer to record the transfer of the Subject Shares to Buyer or its nominee
     upon receipt of the stock certificate(s) evidencing the Subject Shares (it
     being understood that such certificate(s) are currently held by Seller's
     lender).

               (c) On the first Business Day after the Closing, Buyer shall:

                         (i) pay to each Creditor, an amount equal to such
               Creditor's respective portion of the Closing Indebtedness (and in
               the event that the Closing is effective as of 4:00 a.m. (Boston,
               Massachusetts time) on January 1, 2008 plus any accrued interest
               from and after the close of business on the day immediately
               preceding the Closing until such amount is actually paid) in full
               satisfaction thereof and as necessary to cause the release, in
               connection with such repayment, of any security interest,
               mortgage, pledge, lien, conditional sale agreement, security
               title, right of first refusal, right of first offer, preemptive
               right or other encumbrance, restriction or charge of any nature
               (collectively, "Encumbrances") securing such Indebtedness as set
               forth in such Creditor's Payoff Letter; and

                         (iii) pay to each Person to whom the Company or any of
               its Subsidiaries owes a Company Transaction Expense the amount of
               such Company Transaction Expense as set forth in such Person's
               Invoice."

               (d) On the first Business Day after Closing, Seller shall deliver
     or cause to be delivered to Buyer or its Representatives stock
     certificate(s) evidencing all of the Subject Shares.

     SECTION 1.8. AUDITED CLOSING FINANCIAL STATEMENTS. Section 4.13 of the
Agreement is hereby amended and restated in its entirety to read as follows:

          "SECTION 4.13. AUDITED CLOSING FINANCIAL STATEMENTS. As soon as
     reasonably practicable following the Closing Date, but in no event later
     than ninety (90) days following the Closing Date, Seller shall cause, at
     its expense, to have prepared and delivered to Buyer an audited
     consolidated balance sheet of the Company as of the close of business on
     the day immediately prior to the Closing Date, as well as audited
     consolidated statements of operations, cash flows and stockholders' equity
     for the period beginning January 1, 2007 and ending on the close of
     business on the day immediately prior to the Closing Date (the "Audited
     Closing Financial Statements"), accompanied by an audit opinion of KPMG
     LLP. Buyer shall use commercially reasonable efforts to assist Seller and
     KPMG LLP and shall cooperate fully and promptly with Seller and KPMG LLP by
     providing information and providing assistance as Seller or KPMG LLP may
     reasonably request in connection with the preparation of the Audited
     Closing Financial Statements. Seller shall permit KPMG LLP to consult with
     the independent auditors of Buyer in the preparation of the Audited Closing
     Financial Statements and to consider in good faith any recommendations made
     by Buyer's independent auditors in respect thereto. The Audited Closing
     Financial Statements shall fairly present, in conformity with GAAP applied
     on a consistent basis, the consolidated financial position of the Company
     and its Subsidiaries as of the date thereof and the consolidated results of
     operations, cash flows and stockholders' equity


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     of the Company and its Subsidiaries for the periods then ended (subject to
     normal and recurring year-end adjustments that are not, individually or in
     the aggregate, material in magnitude) and shall comply with the applicable
     requirements of the Securities Act (and the related rules and regulations)
     and the applicable requirements of the Exchange Act (and the related rules
     and regulations). At such time as KPMG LLP delivers the Audited Closing
     Financial Statements and its work papers with respect thereto to Seller,
     Seller shall provide copies of such Audited Closing Financial Statements
     and work papers to Buyer."

     SECTION 1.9. CLOSING CONDITIONS. Section 5.2 of the Agreement is hereby
amended and restated in its entirety to read as follows:

     "SECTION 5.2. CONDITIONS TO OBLIGATIONS OF BUYER. The obligations of Buyer
     to consummate the transactions contemplated by this Agreement shall be
     subject to the satisfaction or waiver, at or prior to the Closing, of each
     of the following conditions (each of which is provided for the exclusive
     benefit of Buyer and may be waived by it in whole or in part in its sole
     discretion):

               (a) All covenants contained in this Agreement to be complied with
     by Seller on or before the Closing shall have been complied with in all
     material respects.

               (b) Subject to Section 4.8, (i) each of the representations and
     warranties of Seller contained in Article II that is qualified by
     "materiality" or "Material Adverse Effect" or other similar materiality
     qualifications shall be true and correct in all respects as of the date of
     this Agreement and as of December 26, 2007 as though made on and as of
     December 26, 2007 (except for those representations and warranties set
     forth in Sections 2.1, 2.2 and 2.3, which shall be true and correct in all
     respects as of the Closing Date as though made on and as of the Closing
     Date), except for such representations and warranties that address matters
     only as of a particular date, which shall remain true and correct in all
     respects as of such date, and (ii) each of the representations and
     warranties of Seller contained in Article II that is not qualified by
     "materiality" or "Material Adverse Effect" or other similar materiality
     qualifications shall be true and correct in all material respects as of the
     date of this Agreement and as of December 26, 2007 as though made on and as
     of December 26, 2007 (except for those representations and warranties set
     forth in Sections 2.1, 2.2 and 2.3, which shall be true and correct in all
     respects as of the Closing Date as though made on and as of the Closing
     Date), except for such representations and warranties that address matters
     only as of a particular date, which shall remain true and correct in all
     material respects as of such date.

               (c) No Governmental Authority or court of competent jurisdiction
     shall have enacted, issued, promulgated, enforced or entered any statute,
     rule, regulation, writ, decree, judgment, injunction or other order
     (whether temporary, preliminary or permanent) which is in effect and has
     the effect of making the sale and purchase of the Subject Shares pursuant
     to the terms of this Agreement illegal or otherwise prohibiting
     consummation of the sale and purchase of the Subject Shares.

               (d) The waiting period (and any extension thereof) applicable to
     the consummation of the transactions contemplated by this Agreement under
     the HSR Act shall have expired or been terminated (and there shall not be
     in effect any voluntary agreement between Buyer and the FTC or the DOJ
     pursuant to which Buyer has agreed not to consummate the


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     transactions contemplated by this Agreement for any period of time), and
     any similar waiting period under any applicable foreign antitrust law or
     regulation or other Legal Requirement shall have expired or been
     terminated.

               (e) Subject to Section 4.8, since the date of this Agreement and
     through December 26, 2007, there shall not have occurred any Material
     Adverse Effect.

               (f) Each of the Consents set forth in Schedule 5.2(f) shall have
     been obtained in form and substance reasonably satisfactory to Buyer and
     shall be in full force and effect.

               (g) There shall not be pending or threatened any Legal Proceeding
     by any Governmental Authority: (a) challenging or seeking to restrain or
     prohibit the consummation of the sale and purchase of the Subject Shares;
     (b) relating to the transactions contemplated by this Agreement and seeking
     to obtain from Buyer, the Company or any of its Subsidiaries, any damages
     or other relief that may be material to Buyer, the Company or any of its
     Subsidiaries; (c) seeking to prohibit or limit in any material respect
     Buyer's ability to vote, receive dividends with respect to or otherwise
     exercise ownership rights with respect to any of the Subject Shares; (d)
     that has had or would reasonably be expected to have a material adverse
     effect on the right of Buyer, the Company or any of its Subsidiaries to own
     the assets or operate the business of the Company or any of its
     Subsidiaries; or (e) seeking to compel Buyer, the Company or any of its
     Subsidiaries to dispose of or hold separate any material assets as a result
     of any of the transactions contemplated by this Agreement.

               (h) All Contracts between the Company or any of its Subsidiaries,
     on the one hand, and Seller or any of its Affiliates or Subsidiaries (other
     than the Company and its Subsidiaries and their respective employees in
     their capacity as such), on the other hand, shall have been terminated.

               (i) Buyer shall have received the following agreements and
     documents, each of which shall be in full force and effect (subject to
     Buyer's execution and delivery of the same, to the extent applicable):

                         (i) the Escrow Agreement, executed by Seller and the
               Escrow Agent;

                         (ii) the Condor Agreements, executed by Condor and Alan
               Petroff, as applicable;

                         (iii) a consulting agreement, in the form attached
               hereto as Exhibit C, executed by Jim Barbookles;

                         (iv) employment agreements, in the form attached hereto
               as Exhibit D, executed by each of the individuals identified on
               Schedule 5.2(i)(iv) (the "Key Employees");

                         (v) general releases, in the form attached hereto as
               Exhibit E, executed by each of the Persons identified on Schedule
               5.2(i)(v);


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                         (vi) noncompetition agreements, in the form attached
               hereto as Exhibit F, executed by each of the Persons identified
               on Schedule 5.2(i)(vi);

                         (vii) noncompetition agreements, in the form attached
               hereto as Exhibit G, executed by each of the Persons identified
               on Schedule 5.2(i)(vii);

                         (viii) written resignations of each of the members of
               the board of directors of the Company, each such resignation to
               be effective as of the Closing;

                         (ix) a legal opinion, in the form attached hereto as
               Exhibit H, from Goodwin Procter LLP, legal counsel to Seller;

                         (x) a certificate executed on behalf of Seller by its
               Chief Executive Officer and its Chief Financial Officer (the
               "Seller Closing Certificate") and containing representations and
               warranties of Seller (A) to the effect that the conditions set
               forth in Sections 5.2(a), 5.2(b), 5.2(e) and 5.2(j) have been
               duly satisfied, (B) specifying the total amount of the Closing
               Indebtedness (and attaching thereto an accurate and complete copy
               of each Payoff Letter not previously delivered to Buyer), and (C)
               specifying the total amount of the Company Transaction Expenses
               (and attaching thereto an accurate and complete copy of each
               Invoice not previously delivered to Buyer); and

                         (xi) such forms and certificates, duly executed and
               acknowledged, in form and substance reasonably satisfactory to
               Buyer, certifying that the transactions contemplated by this
               Agreement are exempt from withholding under Section 1445 of the
               Code.

               (j) As of immediately prior to the Closing, each of the Key
     Employees shall remain employed by the Company or one of its Subsidiaries
     and shall not have provided any notice of such Key Employee's intention to
     terminate such employment following the Closing."

     SECTION 1.10. TERMINATION. Section 7.1(d) of the Agreement is hereby
amended and restated in its entirety to read as follows:

               "(d) subject to Section 4.8, by Buyer, upon written notice to
     Seller, if there has occurred a Material Adverse Effect on or prior to
     December 26, 2007;"

     SECTION 1.11. MISCELLANEOUS.

               (a) Except as specifically provided for in this Amendment, the
     terms of Purchase Agreement shall be unmodified and shall remain in full
     force and effect.

               (b) This Amendment, together with the Attachments hereto
     constitute the entire agreement of the parties hereto with respect to the
     subject matter hereof and supersede all prior agreements and
     understandings, written and oral, among the parties with respect to the
     subject matter hereof, other than the Agreement.


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               (c) Except as expressly permitted by the terms hereof, neither
     this Amendment nor any of the rights, interests or obligations hereunder
     shall be assigned by any of the parties hereto without the prior written
     consent of the other parties, except that Buyer may transfer or assign its
     rights and obligations under this Amendment, in whole or from time to time
     in part, to (i) one or more of its Affiliates at any time and (ii) after
     the Closing Date, to any Person; provided that such transfer or assignment
     shall not relieve Buyer of its obligations hereunder or enlarge, alter or
     change any obligation of any other party hereto or due to Buyer.

               (d) This Amendment will be governed by, and construed in
     accordance with, the internal laws of the State of Delaware, regardless of
     the laws that might otherwise govern under applicable principles of
     conflict of laws.

               (e) The parties hereto are sophisticated and have been
     represented by attorneys throughout the transactions contemplated hereby
     who have carefully negotiated the provisions hereof. As a consequence, the
     parties do not intend that the presumptions of laws or rules relating to
     the interpretation of contracts against the drafter of any particular
     clause should be applied to this Amendment or any agreement or instrument
     executed in connection herewith, and therefore waive their effects.

               (f) This Amendment (a) shall be binding upon and inure to the
     benefits of the parties hereto and their respective successors and assigns
     and is not intended to confer upon any other Person any rights or remedies
     hereunder and (b) may be executed in two or more counterparts which
     together shall constitute a single agreement. This Amendment shall become
     effective when each party hereto shall have received a counterpart hereof
     signed by the other party hereto. Until and unless each party has received
     a counterpart hereof signed by the other party hereto, this Amendment shall
     have no effect, and no party shall have any right or obligation hereunder
     (whether by virtue of any other oral or written agreement or other
     communication). The parties hereto agree that irreparable damage would
     occur in the event that any of the provisions of this Amendment were not
     performed in accordance with their specific terms or were otherwise
     breached. It is accordingly agreed that the parties shall be entitled to an
     injunction or injunctions to prevent breaches of this Amendment and to
     enforce specifically the terms and provisions hereof in the Chosen Courts,
     this being in addition to any other remedy to which they are entitled at
     law or in equity. Time is of the essence with respect to the performance of
     this Amendment.

               (g) If any provision of this Amendment or the application thereof
     to any Person or circumstance is held invalid or unenforceable, the
     remainder of this Amendment, and the application of such provision to other
     Persons or circumstances, shall not be affected thereby, and to such end,
     the provisions of this Amendment are agreed to be severable.

               (h) Notwithstanding anything contained herein to the contrary, in
     the event that the Closing does not occur effective as of 4:00 a.m.
     (Boston, Massachusetts time) on January 1, 2008, Sections 1.3, 1.4, 1.5,
     1.6, 1.7, 1.9 and 1.10 of this Amendment shall be deemed null and void,
     such that the provisions of the Agreement proposed to be amended by such
     Sections shall not be so amended and with such provisions being restored as
     originally set forth in the Agreement, unmodified and in full force and
     effect.


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                  [Remainder of page intentionally left blank.]


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     IN WITNESS WHEREOF, the parties hereto have caused this First Amendment to
Stock Purchase Agreement to be signed by their respective officers thereunto
duly authorized, all as of the date first written above.

                                        BUYER:

                                        IDEX CORPORATION


                                        By: /s/ Frank J. Notaro
                                            ------------------------------------
                                        Name: Frank J. Notaro
                                        Title: Vice President


                                        SELLER:

                                        NOVA HOLDINGS, LLC


                                        By:
                                            ------------------------------------
                                        Name:
                                        Title:

<PAGE>

     IN WITNESS WHEREOF, the parties hereto have caused this First Amendment to
Stock Purchase Agreement to be signed by their respective officers thereunto
duly authorized, all as of the date first written above.

                                        BUYER:

                                        IDEX CORPORATION


                                        By:
                                            ------------------------------------
                                        Name:
                                        Title:


                                        SELLER:

                                        NOVA HOLDINGS, LLC


                                        By: /s/ James Barbookles
                                            ------------------------------------
                                        Name: James Barbookles
                                        Title: CHAIRMAN /CEO

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                                  ATTACHMENT A

                                ESCROW AGREEMENT

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                                  ATTACHMENT B

                                 PROMISSORY NOTE