1 EXHIBIT 4.1 Number NICHOLS Shares TXEN Common Stock Common Stock NICHOLS TXEN CORPORATION INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE CUSIP 653823 10 4 This Certifies that SEE REVERSE FOR CERTAIN DEFINITIONS is the owner of full paid and non-assessable shares of common stock of the par value of $0.01 per share of Nichols TXEN Corporation, transferable on the books of the Corporation in person or by Attorney upon surrender of this Certificate properly endorsed. This Certificate is not valid until countersigned and registered by the Transfer Agent and Registrar. Witness the facsimile seal of the Corporation and the facsimile signatures of its duly authorized officers. Dated: Patsy L. Hattox Paul D. Reaves Secretary Chief Executive Officer [SEAL] 2 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) IT TEN -- as joint tenants with right of under Uniform Gifts to Minors survivorship and not as tenants Act ______________________ in common (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 ASSIGNED _______________________________________ ________________________________________________________________________________ (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 __________________ __________________________________________________ THE SIGNATURE TO THIS ABRIDGEMENT MUST CORRESPOND WITH THE NAME AS WRITTEN UPON THE FACE OF THE CERTIFICATE IN EVERY PARTICULAR, WITHOUT NOTICE: ALTERATION OR ENLARGEMENT ON ANY CHANGE WHATEVER. SIGNATURE(S) GUARANTEED:__________________________________________________ THE SIGNATURE(S) SHOULD BE GUARANTEED BY AN ELIGIBLE GUARANTOR INSTITUTION (RANKS, STOCKBROKERS, SAVINGS AND LOAN ASSOCIATION AND CREDIT UNIONS WITH MEMBERSHIP IN AN APPROVED SIGNATURE GUARANTEE MEDALLION PROGRAM, PURSUANT TO S.E.C. RULE 17AD-15. AMERICAN BANK NOTE COMPANY PRODUCTION COORDINATOR: LISA MARTIN: 215-630-2155 660 BLAIR MILL ROAD PROOF OF APRIL 8, 1999 HORSHAM, PA 19044 NICHOLS TXEN CORP. (215) 657-3480 H 80884 bk - ----------------------------------- ------------------------------------------------- SALES: A HOBBS: 404-526-1455 OPERATOR: JW - ----------------------------------- ------------------------------------------------- /NET/BANKNOTE/HOME 13/NICHOLS 60884 NEW - ----------------------------------- -------------------------------------------------