Barrier Bubble lining retains air better than alternative cushioning materials, Polypropylene exterior is moisture puncture and rip resistant, Polypropylene exterior is moisture puncture and rip resistant, Co-extruded seams are heat sealed and burst proof, Self-seal closure features a tamper indicator, Envelope Size: 8-1/2 x 12, Closure: Self-Adhesive, Exterior Material: Polypropylene, Finish: Fine Textured, Color: White, Format/Border: Standard, Envelope/Mailer Interior Dimensions: 8-3/8 x 10-3/4, SKU: AZRSEL37713