Ultralight Bivi is a minimalist bivouac sheet, which is a good way to protect your sleeping bag against intense condensation inside the tent or snow hole. It is made of waterproof, ultra-light Pertex Endurance fabric. A thin membrane responds well to condensation, while providing high breathability. The seams are deliberately placed high away from the ground in order to minimize any possible contact with snow. The bivi is equipped with two stoppers, allowing convenient adjustment of the hood. This product is ideal for protecting a down-filled sleeping bag from moisture. In situations of repeated camping in winter conditions, when there is no easy way of drying your equipment, Ultralight Bivi is a must. Works well with all Cumulus sleeping bags, including a longer version.