#5 10.5 x 16 Inch Usable Space: (10.5 x 15) Easy to use: self-sealing, adhesive and easy to be peeled Self-sealing Fully laminated water proof Kraft Paper Mailers are plain, no printing or branding outside Lightweight 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.