Sea to Summit Ultra-Sil Dry Sack XX-Small (1-Liter) 6" flat x 9"; X-Small (2-Liter) 8" flat x 12" Made of Ultra-Sil nylon, a polyurethane coated Siliconized Cordura for ultimate waterproofing Watertight, non-wicking Hypalon roll top closure with stiffener at the top for a better seal Soft and flexible with a slippery finish for easy packing Nearly transparent allowing good visibility of the contents water-resistant products (such as the Ultra-Sil Stuff Sacks) are siliconized on both sides for ultimate packability waterproof products (such as the UltraSil Dry Sack are) siliconized on the outside and PU-coated on the inside to allow seam taping.