EXHIBIT 4.1 SEE REVERSE SIDE FOR RESTRICTIVE LEGEND NUMBER SHARES 00 00 CAIS INTERNET, INC. INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE 25,000,000 SHARES COMMON STOCK PAR VALUE $0.01 EACH This Certifies that SPECIMEN is the registered holder of XXXXXXXXX Shares fully paid, non-assessable, and transferable only on the books of the Corporation by the holder hereof in person or by Attorney upon surrender of this Certificate properly endorsed. In Witness Whereof, the said Corporation has caused this Certificate to be signed by its duly authorized officers and its Corporate Seal to be hereunto affixed this __________ day of ______________ A.D.________ - -------------------------------- ----------------------------- Secretary Preesident For Value Received, _______________hereby sell, assign and transfer unto ___________________________________ ________________________ Shares represented by the within Certificate, and do hereby irrevocably constitute and appoint __________________________ Attorney to transfer the said Shares on the books of the within named Corporation with full power of substitution in the premises. Dated______________________ ____ In presence of _____________________________ ___________________________ NOTICE: THE SIGNATURE OF 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.