Columbian Tyvek(R) Open-End Envelopes With Releasestrip, 10in; x 13in;, White, Box Of 50 Designed for ultimate protection. Protect what's inside. Superior moisture, burst and tear resistant protection. Convenient and secure self-sealing Grip-Seal closure. Simply peel off release strip and press down for a quick, secure seal. Lightweight white Tyvek material. Open end closure. 10" x 13" 50 envelopes