<PAGE>
                                                                   EXHIBIT 4.1

   NUMBER                                                             SHARES

AB                               [PICTURE]

COMMON STOCK                                                       COMMON STOCK


              INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE

                              ACUITY BRANDS, INC.

THIS CERTIFICATE IS TRANSFERABLE IN
NEW YORK, NEW YORK OR MINNEAPOLIS, MINNESOTA                  CUSIP 00508Y 10 2



This Certifies that
                                                                SEE REVERSE FOR
                                                            CERTAIN DEFINITIONS





is the owner of


 FULLY PAID AND NON-ASSESSABLE SHARES OF THE PAR VALUE OF ONE CENT ($.01) EACH,
                            OF THE COMMON STOCK OF

COUNTERSIGNED AND REGISTERED
         WELLS FARGO BANK MINNESOTA, N.A.
                                                                 TRANSFER AGENT
                                                                  AND REGISTRAR
BY


                                                           AUTHORIZED SIGNATURE


Acuity Brands, Inc. (herein called "the Corporation") transferable on the books
of the Corporation in person or by duly authorized attorney upon surrender of
this Certificate properly endorsed. This Certificate and the shares represented
hereby are issued and shall be held subject to all the process of the
Certificate of Incorporation as amended of the Corporation, a copy of which
Certificate of Incorporation is on file with the Transfer Agent, all of which
the holder by the acceptance hereof expressly assents and is bound. This
Certificate is not valid until countersigned by the Transfer Agent and
registered by the Registrar. Witness the seal of the Corporation and the
signatures of its duly authorized officers.

Dated

                                     [SEAL]



/s/ Helen D. Haines                    /s/   James S. Balloun
    --------------------------             --------------------------
            SECRETARY                        CHAIRMAN OF THE BOARD





                          AMERICAN BANK NOTE COMPANY
<PAGE>


Until the Separation Time (as defined in the Rights Agreement referred to
below), this certificate also evidences and entitles the holder hereof to
certain Rights as set forth in a Stockholder Protection Rights Agreement, dated
as of November 12, 2001 (as such may be amended from time to time, the "Rights
Agreement"), between Acuity Brands, Inc. (the "Company") and Wells Fargo Bank
Minnesota, N.A. as Rights Agent, the terms of which are hereby incorporated
herein by reference and a copy of which is on file at the principal executive
offices of the Company. Under certain circumstances, as set forth in the Rights
Agreement, such Rights may be redeemed, may become exercisable for securities or
assets of the Company or securities of another entity, may be exchanged for
shares of Common Stock or other securities or assets of the Company, may expire,
may become null and void (if they are "Beneficially Owned" by an "Acquiring
Person" or an "Affiliate" or "Associate" thereof, as such terms are defined in
the Rights Agreement, or by any transferee of any of the foregoing) or may be
evidenced by separate certificates and may no longer be evidenced by this
certificate. The Company will mail or arrange for the mailing of a copy of the
Rights Agreement to the holder of this certificate without charge after the
receipt of a written request therefor.


                              ACUITY BRANDS, INC.

A FULL STATEMENT OF THE DESIGNATIONS, PREFERENCES, LIMITATIONS, VOTING RIGHTS
AND RELATIVE RIGHTS OF THE SHARES OF EACH CLASS OF STOCK MAY BE OBTAINED BY ANY
STOCKHOLDER, WITHOUT CHARGE, FROM THE TRANSFER AGENT, OR THE OFFICE OF THE
SECRETARY OF THE CORPORATION.

         The following abbreviations, when used in the inscription on the face
of this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<Table>
  <S>                                                 <C>
  TEN CON -- as tenants in common                     UNIF GIFT MIN ACT -- __________ Custodian __________
  TEN ENT -- as tenant by the entireties                                     (Cust)              (Minor)
  JT TEN  -- as joint tenants with right of                                under Uniform Gifts to Minors
             survivorship and not as tenants
             in common                                                     ACT ___________________________
                                                                                        (State)
</Table>

    Additional abbreviations may also be used though not in the above list.

For value received _______________________ hereby sell, assign and transfer into

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
---------------------------------------

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             PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS OF ASSIGNEE

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____________________________________________________ Shares of the capital stock

represented by the within Certificate, and do hereby irrevocably constitute and
appoint

_____________________________________________________________ Attorney, to

transfer the said stock on the books of the within-named Corporation with full
power of substitution in the premises.

Dated

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NOTICE: THE SIGNATURE TO THIS ASSIGNMENT MUST CORRESPOND WITH THE NAME AS
WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR WITHOUT
ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATEVER.

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THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION
WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM
PURSUANT TO RULE 17Ad-15 UNDER THE SECURITIES EXCHANGE ACT OF 1934, AS AMENDED
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 SIGNATURE(S) GUARANTEED BY:





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<Table>
<S>                                                   <C>
-------------------------------------------------     -------------------------------------------------
           AMERICAN BANK NOTE COMPANY                 PRODUCTION COORDINATOR: LISA MARTIN: 215-764-??26
          55TH STREET AT SANSOM STREET                            PROOF OF OCTOBER 25, 2001
             PHILADELPHIA, PA 15139                                  ACUITY BRANDS, INC.
                 (212) 784-5600                                         H 71319 back
-------------------------------------------------     -------------------------------------------------
         SALES ANDY HOBBS: 404-525-1455                         OPERATOR:                  eg
-------------------------------------------------     -------------------------------------------------
    /NET/BANKNOTE/HOME 23/MAC 6/ACUITYm71319                                 NEW
-------------------------------------------------     -------------------------------------------------
</Table>