Tyvek Lightweight Security EnvelopeDuPont® Lightweight Tyvek® is strong and moisture resistant, yet light as a cloud in weight. Security of contents is enhanced by an inside printed tint pattern. Convenient Redi-Strip® closure requries no moisture to seal and features a removable strip that provides a clean, quick seal upon contact. The peel-off strip protects adhesive from dust for longer shelf life. Treated with an antimicrobial agent to protect the envelope from the growth of bacteria, mold, mildew, fungus and odors. Envelope Size: 4 1/8 x 9 1/2; Envelope/Mailer Type: Business/Trade; Closure: Redi-Strip®.