Thermarest Waterproof Stuff Sack X-Large Waterproof: Roll-down closure and taped seams ensure your mattress stays dry. Durable: 210-denier coated nylon stands up to the toughest conditions. Easy to Transport: Handy D-ring and end handle make sacks easy to secure and unpack. Versatile: Also great for storing ammo, dry clothes, and other hunting essentials. Weight: 5oz. Dimensions: 7.5x38in.