The Ultra-Sil Compression Dry Sack is a super lightweight dry sack designed to compress bulky clothing or other squishable gear that lives inside your pack. Made from Ultra-Sil 30D CORDURA Nylon fabric with an eVent fabric base, the air can be squeezed out but water can't get in. It's an ideal option for use inside a backpack during longer lightweight hikes, adventure travels, cycle touring and any activity where you need to maximize pack space by compressing your bulky items. It employs waterproof seams, a hypalon roll-top, non-wicking closure and is super lightweight.