This brilliant compression sack is made from 70D waterproof & seam sealed durable nylon fabric with an e Vent base panel. The e Vent panel is totally waterproof & highly air permeable, which allows air to escape as you compress the bag. You can actually feel the air coming out! A Hypalon roll top closure keeps the contents dry & secure & does not wick moisture. The webbing compression straps makes compressing bulkier items, such as sleeping bags, easy & also act as handy carry straps. Air compresses out, water cannot get in Compact & lightweight Waterproof & air permeable e Vent fabric base Waterproof seams, double stitched & fully tape sealed 10, 000mm hydrostatic head, lightweight durable Nylon fabric Hypalon roll top closure does not wick moisture Reinforced stitching on all stress points