Refuel on your next cold backpacking adventure in the ultralight, eco-friendly Hydrogen 30° Sleeping Bag, featuring a new sustainable ExpeDry water-repellent technology that increases down performance and reduces the drying time. With an optimal ISO-tested comfort right around freezing, the Hydrogen will give you the warmth you need in a super-packable 800-fill-power down bag designed to easily stuff into any overnight pack. A thru-hiking favorite, the new gas bags provide lightweight warmth that's light on the Earth—perfect when you're looking to maximize miles or speed in the mountains and minimize weight and space in your pack. If going tent-less or camping with the car is in the plan, the Hydrogen will perform as a bivvy and a super-lofty trunk or rooftop snoozer.