Description This is a bag for the serious mountaineer, planning on spending some quality time with Mother Nature's dark side. It is a serious bag for serious conditions. Rated to -40°C Features Differentially cut (outer is cut bigger than inner) 3-Dimensional construction Overfilled chest and foot sections Built-in cowl and oversized inside hood ensures a snug fit Twin collar baffle for maximum heat retention Tested on Mt. Everest Specifications Dimensions: 240 cm Down Ratio: 92/8 Fill Power: 650 Material(s) Microtex Ripstop Nylon (Outer), Microtex 5000 (Inner) First Ascent Xtreme Blue Wolf Down Sleeping Bag