Sea to Summit Ultra-Sil Pack Liner Ultra-Sil Pack Liner opens wide for easy packing when its inside a pack Unique top closure: extra fabric at the top folds in and velcros in place, then rolls down, creating a more compact closed loop at the top Made of PU coated Siliconized Cordura. Non-wicking Hypalon roll-top closure with stiffener at the top for a better seal Fully seam sealed. Uses low profile buckles. Slippery finish for easy packing Dimension/Weight: SMALL 19"x 6" (oval base), 21" H, 2.6oz. MEDIUM 20" x 8" base, 35" H, 3.4 oz. LARGE: 22" x 10", 48" H, 4.4 oz