DESC: The Outdoor Research DryComp Summit Sack keeps your clothes or sleeping bag dry and converts to an ultralight backpack when it's time to head for the top. The DryComp Summit Sack is made of Hydroseal-coated Antron nylon and is seam taped to make it fully waterproof. A roll-top closure on this Outdoor Research stuff sack holds out moisture, and compression straps shrink your load. When you pack up on summit day, leave your huge mountaineering pack behind. The 12.2oz, 1885cu in Summit Sack has two backpack straps and holds all your necessities for the final push to the top.