The Marmot Atom Mummy Sleeping Bag features ultra light design and high quality down, giving it cult status among alpinists, as a bivvy bag on extreme climbs. A great bag for warm weather nights on casual summer road trips, the full update with changes like curved baffles that reduce shifting down and a fold down second zipper for ventilation makes this bag even more comfortable than before. Filled and finished in the USA. Certified 800 fill power goose down insulation. Shell is Pertex 20d 100% nylon ripstop DWR 1.03ozyd. Lining is 30d 100% nylon DWR 1.09 ozyd. Fold down second zipper provides added ventilation and easy access. Full length locking YKK zipper with zip guard slider to reduce snagging. Anatomically designed footbox with wrap around construction increases warmth. Smooth curved baffles reduce down shifting. Nautilus multi baffle hood limits heat loss. Sewn through baffles. EN tested. Comfort: 44.1F6.7C Lower Limit: 35.4F1.9C Extreme: 8.4F 13.1C 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.