The sea to summit ultrasil dry sack delivers optimal waterproofing for your gear without compromising on weight crafted from siliconized cordura this sea to summit dry sack is 50 percent lighter than previous models and has a higher strength to weight ratio than most other waterproof materials on the market the ultrasil features reinforced stitching which provides greater durability and increases longevity and the hypalon roll top closure effectively keeps the sack completely sealed ensuring