Simple construction and a classic mummy bag shape are the hallmarks of one of our best-selling sleeping bags for backpackers who put a premium on low weight, incredible comfort and straightforward tech. The Nitro 0 sleeping bag is designed with durable nylon ripstop and insulated with 800-fill, hydrophobic DriDown to keep you toasty warm, even on damp nights. A draft collar seals in the heat when moving around, and sidewall baffles prevent the down from shifting and causing cold spots, but our patented self-sealing foot vent provides relief to hot sleepers without the need to kick off the covers. Top it off with an anti-snag zipper to eliminate sleepy struggles and take greater comfort with this intuitive mummy bag.