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                                                                    Exhibit 4.13

      Neither the options granted pursuant to this Agreement nor any shares of
      Common Stock issuable upon the exercise of any such options have been
      registered under the Securities Act of 1933 and none of them may be
      transferred, nor will any assignee or endorsee of such options or shares
      of Common Stock be recognized as an owner thereof by the issuer for any
      purpose, unless a registration statement under the Securities Act of 1933,
      as amended, with respect to such options or shares shall then be in effect
      or unless the availability of an exemption from registration with respect
      to any proposed transfer or disposition of such options or shares shall be
      established to the satisfaction of the issuer. Neither the options granted
      pursuant to this Agreement nor any shares of Common Stock issuable upon
      the exercise of any such options may be sold or transferred except
      pursuant to an effective registration statement or similar qualification
      under applicable State securities laws, or unless it is established to the
      satisfaction of the issuer that such sale or transfer is in a transaction
      which is exempt under, or otherwise in compliance with, such laws. Neither
      the options granted pursuant to this Agreement nor any shares of Common
      Stock issuable upon the exercise of any such options may be sold,
      transferred, assigned or otherwise disposed of, except in accordance with
      the terms and conditions of a certain Stockholders' Agreement dated as of
      December 21, 1990 by and among the issuer, the holder of this option and
      the other stockholders named in such Stockholders' Agreement.

                               CVC HOLDINGS, INC.
                             c/o CVC Products, Inc.
                                  525 Lee Road
                              Rochester, N.Y. 14603

To: Christopher Mann

            1. OPTION GRANT. CVC Holdings, Inc. (the "Company") hereby grants to
you, effective as of December 21, 1990 (the "Date of Grant"), in consideration
of the payment to the Company of $3,350 (such being an aggregate of $.67 for
each option to purchase a Share (as hereinafter defined) granted hereby), the
receipt of which is hereby acknowledged by the Company, the option (this
"Option") to purchase, in accordance with and subject to the terms and
conditions set forth herein, 5,000 shares (the "Shares") of Common Stock, $.01
par value per share ("Common Stock"), of the Company, at the exercise price of
$25 per Share, subject to adjustment as hereinafter provided ("the Option
Price"), such Option Price being, in the judgment of the Company, not less than
one hundred percent (100%) of the fair market value of each such Share on the
Date of Grant and intended to reflect the parties' best estimate as to what is
likely to be not less than the fair market value of each such Share on the date
of exercise of this Option.

            2. OPTION EXERCISE. This Option may be exercised by you from time to
time, in part or in full (but subject to the provisions of subparagraph 2(b) and
of Paragraph 4 below), at any time on or after the date hereof.
<PAGE>

                  (a) This Option can be exercised only with respect to full
Shares and only with respect to a minimum of 200 Shares at the time of any
exercise.

                  (b) Any exercise of this Option must be in writing addressed
to the Board of Directors of the Company at the principal place of business of
the Company and delivered at least ten (10) business days prior to the proposed
date of exercise, which writing shall indicate the number of Shares as to which
this Option is being exercised and shall be accompanied by a certified or bank
cashier's check payable to the order of the Company in the full amount of the
aggregate Option Price of the Shares covered by such exercise.

            3. TERMINATION OF OPTION. The unexercised portion of this Option
will automatically and without notice terminate and become null and void on the
tenth anniversary of the date hereof, subject to earlier termination as
hereinafter provided (the date on which the earliest of such events shall occur
being herein referred to as the "Expiration Date").

            4. CERTAIN CONDITIONS TO EXERCISE. (a) This Option may be exercised
by you only if on the date of exercise you satisfy the Company in such manner as
the Company shall reasonably specify, that the Shares issuable upon such
exercise may be issued to you pursuant to an exemption from the registration
requirements of applicable federal and state securities laws.

                  (b) This Option may not be exercised if and so long as such
exercise would subject the Company or any of its subsidiaries to any substantial
risk under contracts or programs restricting foreign ownership or control of the
Company or any of its subsidiaries or would subject the Company or any of its
subsidiaries to other regulatory problems, in each case, as determined by the
Company's Board of Directors.

            5. RESERVATION OF SHARES. The Company will at all times through the
close of business on the Expiration Date reserve and keep available free from
preemptive rights, out of the aggregate of its authorized but unissued or
treasury shares of Common Stock, for the purpose of enabling it to satisfy any
obligation to issue shares of Common Stock upon exercise of this Option, the
number of Shares deliverable upon the exercise of this Option. The Company
covenants that all Shares issued upon exercise of this Option shall, upon
issuance in accordance with the terms of this Option, be fully paid and
nonassessable.

            6. CERTAIN ADJUSTMENTS; MERGERS, CONSOLIDATIONS, ETC. (a)
Notwithstanding any other provisions contained in this Agreement, in the event
of the merger or consolidation of the Company, or reorganization or
recapitalization of, stock dividend on, stock split, split-up, split-off,
spin-off or combination of, shares of Common Stock, appropriate adjustments
shall be made by the Board of Directors of the Company as to the number of
Shares and/or the exercise price per Share subject to this Option, as shall be
equitable to prevent reduction or enlargement of rights under this Option, and
the determination of the Board of Directors as to such matters shall be
conclusive and binding. References in this Agreement to Shares shall include any
such securities or other property (including cash) into which Shares of Common
Stock may be changed pursuant to or in accordance with the preceding sentence
through merger, consolidation,


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reorganization, recapitalization, stock dividend, stock split, split-up,
split-off, spin-off, or combination of shares.

                  (b) If (i) the Board of Directors of the Company approves a
consolidation or merger of the Company or any substantial subsidiary of the
Company with another corporation and a change in control in the Company is
effected in connection therewith, or (ii) the Board of Directors approves the
sale of all or substantially all of the property or assets of the Company or of
any substantial subsidiary of the Company, or (iii) more than fifty percent
(50%) of the total combined voting power of all classes of stock of the Company
normally entitled to vote for the election of directors of the Company is
acquired by a person, firm or corporation or cooperating group of such
individuals or entities, other than the Initial Stockholders or their Groups (as
such terms are defined in the Stockholder's Agreement (as hereinafter defined)),
the Board of Directors shall have the right to terminate this Option (in which
event such Option shall not be subject to the above described adjustments in
subparagraph (a)) by causing written notice of such termination to be given to
you at least fifteen (15) days prior to the earlier of (A) the date on which
such consolidation, merger or acquisition of assets or stock is expected to
become effective, or (B) if different from the date specified in subclause (A)
above, the date as of which a record will be taken to determine the holders of
shares of Common Stock who shall be entitled to exchange such shares for
securities or other property (including cash) deliverable upon such
consolidation, merger or acquisition of assets or stock. Such notice shall be
deemed duly given when given as provided below, and failure to give such notice,
or a defect therein, shall not affect the termination of this Option.

                  (c) If the Board of Directors shall determine to cause the
termination of this Option pursuant to subparagraph (b) above upon the
occurrence of an event described in said subparagraph (b), and shall not provide
a period during which this Option will be exercisable in full prior to such
termination of this Option or in the event the restrictions set forth in
Paragraph 4 shall apply to the Options to be terminated, then, upon the
occurrence of such event and the actual consummation of the applicable
consolidation, merger or sale, this Option shall terminate and you shall
receive, with respect to each Share subject to this Option, an amount per Share
equal to the excess of the fair market value of each such Share immediately
prior to the occurrence of such transaction over the exercise Option Price per
Share; such amount to be payable in cash, in one or more of the kinds of
property payable in such transaction, or in a combination thereof, as the Board
of Directors, in its sole discretion, shall determine.

            7. RESTRICTIONS ON TRANSFERS. (a) This Option is not transferable by
you, and is exercisable only by you, and may not be sold, assigned, transferred,
pledged or hypothecated in any way (whether by operation of law or otherwise)
except if and to the extent expressly permitted pursuant to the Stockholders'
Agreement (the "Stockholders' Agreement") dated as of the date hereof among the
Company and each of the holders of shares of capital stock of the Company named
therein, and shall not be subject to execution, attachment or similar
proceeding. Any attempted assignment, transfer, pledge, hypothecation or other
disposition of this Option or any interest herein, and the levy of any
attachment or similar proceeding upon this Option or any


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<PAGE>

interest herein, shall be null and void and without effect except as provided in
the preceding sentence.

                  (b) The Company may postpone the time of delivery of
certificates for the shares issuable upon the exercise of this Option for such
additional time as the Company shall deem necessary or desirable to enable it to
comply with the listing requirements of any securities exchange or the National
Association of Securities Dealers, Inc. upon which shares of the Company may
then or are then contemplated to be listed, or the requirements of the
Securities Act of 1933, as amended (the "Securities Act"), or the Securities
Exchange Act of 1934, as amended, or any rules or regulations of the Securities
and Exchange Commission promulgated thereunder or the requirements of applicable
state laws relating to the authorization, issuance or sale of securities.

                  (c) You acknowledge that all of the restrictions on the sales
of the Options and/or shares acquirable upon the exercise of any Options and the
representations and warranties made by you in the Stockholders' Agreement and in
the Subscription Agreement, dated as of the date hereof, between you and the
Company are incorporated herein by reference as if set forth in full herein.

            8. MISCELLANEOUS. (a) You shall not have any rights to dividends or
any other rights of a stockholder with respect to any shares subject to this
Option, except to the extent that you have paid for such Shares and a
certificate for such shares shall have been actually issued in your name upon
the due, proper and timely exercise of this Option as provided for herein.

                  (b) Each notice relating to this Option shall be in writing
and delivered in person or by certified mail, return receipt requested, to the
proper address. All notices to you shall be addressed to you at your address
below specified. All notices to the Company shall be addressed to the Company at
the address set forth on the first page of this Agreement. Anyone to whom a
notice may be given under this Agreement may designate a new address by notice
to that effect given to the other party in accordance with this subparagraph
(b).

                  (c) You understand that, upon exercise of this Option, you
will recognize income for tax purposes in an amount equal to the excess of the
then fair market value of the Shares purchased over the Option Price for such
Shares. Your employer may withhold tax from your current compensation with
respect to such income; to the extent that your then current compensation is
insufficient to satisfy the withholding tax liability, you will be required to
make a cash payment to cover such liability as a condition of exercise of this
Option.

                  (d) If this Option shall be mutilated, lost, stolen or
destroyed, the Company shall issue in exchange and substitution for and upon
cancellation of the mutilated Option, or in lieu of and in substitution for the
Option lost, stolen or destroyed, a new Option of like tenor and denomination,
but only upon receipt of evidence satisfactory to the Company of such loss,
theft or destruction of such Option and such indemnity and, if requested by the


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Company, such bond, as shall in each case be satisfactory to the Company. You
must also comply with such other reasonable regulations and pay such other
reasonable charges as the Company may prescribe in connection with such
issuance.

                  (e) This Option shall be governed and construed in accordance
with the substantive laws of the State of New York applicable to contracts
executed, delivered and to be fully performed in the State of New York, without
giving effect to contrary provisions regarding conflict of laws.

                  (f) This Agreement shall inure to the benefit of and shall be
binding upon your heirs, executors, administrators, successors and legal
representatives, and shall inure to the benefit of and be binding upon the
Company and its successors and assigns. You may not assign, transfer, pledge,
encumber, hypothecate or otherwise dispose of this Agreement, or any of your
rights hereunder except if and to the extent expressly permitted by the
Stockholders' Agreement referred to above, and any such attempted prohibited
delegation or disposition shall be null and void and without effect.

                  (g) This Agreement constitutes the complete understanding
between the parties with respect to the subject matter hereof, and no statement,
representation, warranty or covenant has been made by either party with respect
thereto except as expressly set forth herein. This Agreement shall not be
altered, modified, amended or terminated except by written instrument signed by
each of the parties hereto.

                  (h) This Agreement may be executed in any number of
counterparts, each of which shall be deemed an original but all of which shall
constitute one and the same instrument.

                  (i) The paragraph headings contained herein are for the
purposes of convenience only, are not intended to define or limit the contents
of said paragraphs and are not part of this Agreement.


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                  (j) By signing below, you hereby accept this Option subject to
all of the terms and provisions hereof and acknowledge all of the
representations, warranties and agreements set forth above. This Option shall
not be effective until you have signed this Option and delivered it to the
Company.

            IN WITNESS WHEREOF, CVC Holdings, Inc. has caused this Option to be
executed as of the day of December 21, 1990.

                                    CVC HOLDINGS, INC.


                                    By: /s/ CHRISTINE B. WHITMAN
                                        ---------------------------------

ACCEPTED AND AGREED TO:


/s/ CHRISTOPHER MANN
-------------------------------
(716) 225-7248
702 WERTH GREECE RD
ROCHESTER, NY 14026
-------------------------------
[Address]


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