Tally up the ultra light fabric, high lofty down and a minimalist design, and the Marmot Lithium Winter Sleeping Bag  stacks up to be Marmot's lightest bag for mountaineers and backpackers. Good in conditions down to zero degrees Fahrenheit or -18°C, the updated design features on this bag help reduce shifting down and increase ventilation. Features Fold-down second zipper provides added ventilation, easy access. Anti-snag slider reduces snagging Anatomically designed footbox with wrap-around construction increases warmth Smooth-curved baffles reduce down shifting. Nautilus multi-baffle hood limits heat loss Filled and finished in Rohnert Park, California Certified 800+ Fill power goose down Ultralight Pertex microlight 20d 100% nylon ripstop DWR 1.03 oz/sqyd EN tested Full length locking YKK two way zipper with zip-guard slider Down defender to improve water-resistance in wet conditions Internal stash pocket Snagless insulated draft tube Two way zipper sliders Hood draw cord Zipper garage Stretch tricot baffles Two hang loops Stuff and storage sack included Marmot Lithium -18°C Lightweight Winter 800 + Loft Down Sleeping Bag