100% Reusable and Resealable: Simple materials, excellent performance; Made in the USA. 20+ YEARS OF EXPERIENCE. Style: Flat. Size: 12 3/4 X 15. Part Number: Burm4Ss. Columbian 9 Security Envelopes, 500/Box, Double Window, 3-7/8 x 8-7/8, Releas.