The ultra-sil ™ compression waterproof bag is an ultra-light dry bag designed to compress large clothes or other equipment that can be inside your backpack.Made from Ultra-Sil ™ 30D Cordura® nylon fabric with an Event® fabric base, the air can be deployed but can not go home. It's an ideal option for use inside a backpack during long light hikes, adventure trips, cycling tours and any activity where you need to maximize storage space by compressing your bulky items to a third of their volume.It uses impervious seams, a hilly winding closure, an anti-wick closure and is super light.