Size: 8.5” x 12” Usable Space: 8.5” x 11”Self-sealing, adhesive and easy to be peeledKeeps your contents secure and tamper-proof. Extremely durable yet lightweight. The poly material helps to save on postage. Strong seams with fins on two sides and a seamless bottom provides maximum protection. Surface easily accepts ink, stamps, and labels. Approved by USPS, FedEx, UPS, and DHL.