The Sphere Bivi from Mammut is an uncompromising and very lightweight bivouac bag that should be an essential piece of equipment on any tour. It is equipped with rope openings, a drawstring and an integrated stuff bag. The upper part consists out of a breathable membrane with a water column of 15,000mm and a water vapor permeability of 15,000 g/m². The bottom part consists out of a waterproof nylon fabric with a water column of 5,000 mm.