Winner of National Geographic's 2014 Gear of the Year Award 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. Brilliant! "This bag has an inflatable sleeping pad built in. So instead of carrying two pieces of gear, I now carry one. Brilliant! The stuff sack has compression straps to cinch the bag down, so it packs even smaller than the one I hauled along the Pacific Crest Trail. Don't lose sleep over the slightly rubbery pad—or the steep price. You can't overvalue how great it feels to wake up rested and ready to crush the trail." — Cheryl Strayed, author of Wild, reviewed in The Best Cold Weather Gear — Men's Health November, 2014 15D PERTEX® NYLON SHELL Ultralight, tough fabric 850 FILL STORMDOWN™ POWERED BY DOWNTEK™ Top of bag insulated with cutting edge DWR goose down that insulates even in wet conditions CLIMASHIELD® HL INSULATION Bottom of bag insulated with high-loft synthetic INTEGRATED, INFLATABLE SLEEP PAD Patent-pending design includes a hand pump in stuff sack