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                                                                    EXHIBIT 3.18


                          CERTIFICATE OF INCORPORATION

                                       OF

                         PROSOURCE MEXICO HOLDINGS, INC.

The undersigned, natural persons, for the purpose of organizing a corporation
for conducting the business and promoting the purposes hereinafter stated, under
the provisions and subject to the requirements of the laws of the State of
Delaware (particularly Chapter 1, Title 8 of the Delaware Code and the acts
amendatory thereof and supplemental thereto, and known, identified, and referred
to as the "General Corporation Law of the State of Delaware"), hereby certify
that:

FIRST: The name of the corporation (the "Corporation") is PROSOURCE MEXICO
HOLDINGS, INC.

SECOND: The address, including street, number, city, and county, of the
registered office of the Corporation in the State of Delaware is 32 Loockerman
Square, Suite L-100, City of Dover, County of Kent; and the name of the
registered agent of the Corporation in the State of Delaware at such address is
The Prentice-Hall Corporation System, Inc.

THIRD: The purpose of the Corporation is to engage in any lawful act or activity
for which corporations may be organized under the General Corporation Law of the
State of Delaware.

FOURTH: The total number of shares of capital stock which the Corporation shall
have the authority to issue is one thousand shares consisting of Common Stock
having a par value of $1.00 per share.

FIFTH:  The name and the mailing address of the incorporator are as follows:



           NAME                        MAILING ADDRESS
           ----                        ---------------
                                        

           Gary J. Cohen               c/o Fine Jacobson Schwartz
                                            Nash & Block
                                       100 S.E. 2nd Street
                                       Suite 3600
                                       Miami, Florida  33131


SIXTH:  The Corporation is to have perpetual existence.
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SEVENTH: Whenever a compromise or arrangement is proposed between this
Corporation and its creditors or any class of them and/or between this
Corporation and its stockholders or any class of them, any court of equitable
jurisdiction within the State of Delaware may, on the application in a summary
way of this Corporation or of any creditor or stockholder thereof or on the
application of any receiver or receivers appointed for this Corporation under
the provisions of Section 291 of Title 8 of the Delaware Code or on the
application of trustees in dissolution or of any receiver or receivers appointed
for this Corporation under the provisions of Section 279 of Title 8 of the
Delaware Code order a meeting of the creditors or class of creditors, and/or of
the stockholders or class of stockholders of this Corporation, as the case may
be, to be summoned in such manner as the said court directs. If a majority in
number representing three fourths (3/4) in value of the creditors or class of
creditors, and/or of the stockholders or class of stockholders of this
Corporation, as the case may be, agree to any compromise or arrangement and to
any reorganization of this Corporation as a consequence of such compromise or
arrangement, the said compromise or arrangement and the said reorganization
shall, if sanctioned by the court to which the said application has been made,
be binding on all the creditors or class of creditors, and/or on all the
stockholders or class of stockholders, of this Corporation, as the case may be,
and also on this Corporation.

EIGHTH: For the management of the business and for the conduct of the affairs of
the Corporation, and in further definition, limitation, and regulation of the
powers of the Corporation and of its directors and of its stockholders or any
class thereof, as the case may be, it is further provided:

         1. Subject to those matters reserved to the stockholders of the
Corporation as set froth in the Bylaws, the management of the business and the
conduct of the affairs of the Corporation shall be vested in its Board of
Directors. The number of directors which shall constitute the whole Board of
Directors shall be fixed by, or in the manner provided in, the Bylaws. The
phrase "whole Board" and the phrase "total number of directors" shall be deemed
to have the same meaning, to wit, the total number of directors which the
Corporation would have if there were no vacancies. No election of directors need
be by written ballot.


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         2. The power to adopt, amend, or repeal the Bylaws of the Corporation
may be exercised only by the stockholders of the Corporation entitled to vote.

         3. Whenever the Corporation shall be authorized to issue only one (1)
class of stock, each outstanding share shall entitle the holder thereof to
notice of, and the right to vote at, any meeting of stockholders. Whenever the
Corporation shall be authorized to issue more than one class of stock, no
outstanding share of any class of stock which is denied voting power under the
provisions of the certificate of incorporation shall entitle the holder thereof
to the right to vote at any meeting of stockholders except as the provisions of
paragraph (2) of subsection (b) of Section 242 of the General Corporation Law of
the State of Delaware shall otherwise require; provided, that no share of any
such class which is otherwise denied voting power shall entitle the holder
thereof to vote upon the increase or decrease in the number of authorized shares
of said class.

NINTH: The personal liability of the directors of the Corporation is hereby
eliminated to the fullest extent permitted by the provisions of paragraph (7) of
subsection (b) of Section 102 of the General Corporation Law of the State of
Delaware, as the same may be amended and supplemented.

TENTH: The Corporation shall, to the fullest extent permitted by the provisions
of Section 145 of the General Corporation Law of the State of Delaware, as the
same may be amended and supplemented, indemnify any and all persons whom it
shall have power to indemnify under said section from and against any and all of
the expenses, liabilities, or other matters referred to in or covered by said
section, and the indemnification provided for herein shall not be deemed
exclusive of any other rights to which those indemnified may be entitled under
any Bylaw, agreement, vote of stockholders or disinterested directors or
otherwise, both as to action in his official capacity and as to action in
another capacity while holding such office, and shall continue as to a person
who has ceased to be a director, officer, employee, or agent and shall inure to
the benefit of the heirs, executors, and administrators of such a person.

ELEVENTH: From time to time, any of the provisions of this certificate of
incorporation may be amended, altered, or repealed, and other provisions
authorized by the laws of the State of Delaware at the time in force may be
added or inserted in the manner 


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and at the time prescribed by said laws, and all rights at any time conferred
upon the stockholders of the Corporation by this certificate of incorporation
are granted subject to the provisions of this Article ELEVENTH.

Signed on January 15, 1993.


                                       /s/ Gary J. Cohen
                                       ---------------------------
                                       GARY J. COHEN, Incorporator



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