EXHIBIT 4.1 NUMBER SHARES TMX THERMATRIX INC. INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE THIS CERTIFICATE IS TRANSFERABLE IN SEE REVERSE FOR STATEMENTS RELATING THE CITY OF BOSTON, MA OR NEW YORK, NY TO RIGHTS, PREFERENCES, PRIVILEGES AND RESTRICTIONS, IF ANY This Certifies that CUSIP 883550 10 5 is the record holder of FULLY PAID AND NONASSESSABLE SHARES OF COMMON STOCK, $.001 PAR VALUE, OF THERMATRIX INC. transferable only on the books of the Corporation by the holder hereof in person or by duly authorized Attorney upon surrender of this certificate properly endorsed. This certificate is not valid until countersigned by the Transfer Agent and registered by the Registrar. WITNESS the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers. Dated (Signature) (Signature) - ------------------------ ------------------------------------ SECRETARY CHAIRMAN AND CHIEF EXECUTIVE OFFICER [CORPORATE SEAL OF THERMATRIX INC. MARCH 5, 1996 * DELAWARE *] COUNTERSIGNED AND REGISTERED: THE FIRST NATIONAL BANK OF BOSTON TRANSFER AGENT AND REGISTRAR BY [Signature] - ---------------------------- AUTHORIZED SIGNATURE AMERICAN BANK NOTE COMPANY MAY 20, 1996 3504 ATLANTIC AVENUE SUITE 12 LONG BEACH, CA 90807 043654fc (310) 989-2333 (FAX) (310) 426-7450 308-19X REV 2 A statement of the powers, designations,preferences and relative, participating, optional or other special rights of each class of stock or series thereof and the qualifications, limitations or restrictions of such preferences and/or rights as established, from time to time, by the Certificate of Incorporation of the Corporation and by any certificate of determination, the number of shares constituting each class and series, and the designations thereof, may be obtained by the holder hereof upon request and without charge at the principal office 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: TEN COM -- as tenants in common UNIF GIFT MIN ACT-- __________Custodian_____________ TEN ENT -- as tenants by the entireties (Cust) (Minor) JT TEN -- as joint tenants with right of under Uniform Gifts to Minors survivorship and not as tenants Act____________________________ in common (State) UNIF TRF MIN ACT-- ______Custodian (until age ____) (Cust) ________ under Uniform Transfers (Minor) to Minors Act___________________ (State) Additional abbreviations may also be used though not in the above list. FOR VALUE RECEIVED, _____________________________ hereby sell, assign and transfer unto PLEASE INSERT SOCIAL SECURITY OR OTHER IDENTIFYING NUMBER OF ASSIGNEE - ----------------------------------------- - ----------------------------------------- - -------------------------------------------------------------------------------- (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING ZIP CODE, OF ASSIGNEE) - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------------- - -------------------------------------------------------------------------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 ---------------------------- X _____________________________________________ X _____________________________________________ THE SIGNATURE(S) TO THIS ASSIGNMENT MUST NOTICE: CORRESPOND WITH THE NAME(S) AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT ALTERATION OR ENLARGEMENT OR ANY CHANGE WHATSOEVER. Signature(s) Guaranteed By ----------------------------------------- THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (BANKS, STOCKHOLDERS, SAVINGS AND LOAN ASSOCIATIONS AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM), PURSUANT TO S.E.C. RULE 17ad-15. - -------------------------------------------- AMERICAN BANK NOTE COMPANY MAY 16, 1996 3504 ATLANTIC AVENUE SUITE 12 LONG BEACH, CA 90807 043654bk (310) 989-2333 (FAX) (310) 426-7450 REV 1 - ---------------------------------------------