Our guide team built this bag with one idea. Set a new standard for fast and light performance without sacrificing safe and warm. Best–in–class materials include an ultralight, tough, 15–denier Pertex® nylon shell. Top of the bag is insulated with 850 fill StormDown™ powered by DownTek™. The cutting edge DWR technology makes the goose down highly resistant to moisture, retaining its loft and full insulating power even in wet conditions. Bottom of the bag is insulated with ClimaShield® HL synthetic for superior performance in all weather. A patent–pending design integrates an inflatable, insulated pad that's sewn directly into the bag. No need to carry a separate pad, and no extra straps, sleeves, hooks, hardware, or packaging. The stuff sack includes a built–in hand pump for inflating the pad. A true minimalist. With full–throttle performance.