The North Face Inferno is an expedition sleeping bag filled with the warmest insulation Mother Nature makes, European 800+ fill goose down. The Inferno Endurance is a bonafide mountaineer's bag that keeps you warm down to -40F, and is riddled with the burliest features that make The North Face bags so bomber. Waterproof, breathable Shadowlite HyVent shell keeps the down fill dry when tent condensation is dripping. An adjustable down-filled draft collar seals precious heat in and feels nice on your skin. A head-level watch pocket will ensure you rise n' shine at 2am for the final assault to the summit.