A premium 800-fill goose down, 20 degree sleep system that offers superior warmth, unmatched comfort and versatility for the ultra-lite purist. Waterproof Pertex® Endurance Arid Zones™ at the head and foot of the bag protect against condensation in critical areas. The comforter-style top can be attached directly to a sleep pad at variable girths for ideal temperature regulation. Sleeping Bag Specs Rating: 20 deg F | -7 deg C 1 lb 3 oz. | 540 g Still the warmest and most compressible insulation available GoLite uses premium quality 800- and 600-fill power goose down. Down is still the most thermally efficient insulation available, i.e. it provides more warmth for its weight than any other insulation available. Down is also superior in its drape, comfort, lifespan, and compressibility. Nature is an incredible thing. Unmatched warmth-to-weight ratio: down’s fine filaments reach out into its surroundings and create dead air space that slows the escape of warm air, doing it better than any synthetic. More compressible and durable than synthetic insulations, and it retains its loft better over time. Pertex Endurance Waterproof-breathable Features 6" baffles, differentially cut with 5" loft Bottomless design 2 grosgrain straps with buckles to hold pad Snap & drawcord to secure at neck Uses Cold weather outings