Western Mountaineering Bison V

Gore Dry-Loft shell. I must begin by stating I am a total gear head. Before purchase I spent four months researching the highest rated cold weather bags from The North Face, Marmot, Moonstone, Feathered Friends and several other manufacturers. Having just returned from Mt. Mckinley I cannot give enough praise to the Western Mountaineering Bison V. I was using a Gregory "Dru" backpack, somwhat small for most folks on McKinley, dispite the 10 inches of loft this bag has, I was able to get it into the lower compartment of the pack. Both my tent mates had to use VBL liners and bivy sacs in their sleeping systems. (which added considerable weight) It was not untill 14,200 that I even zipped my bag fully closed. Nighttime temps. routinely reach -25 F and at no time was I even slightly chilled. We had three people in a North Face expedition 25 tent which accumulated a significant amount of condensation each night, dispite the moisture the down stayed dry. Upon returning to civilazation I washed the bag with Nixwax down wash. After the washing the bag appeared even loftier than before. Although somewhat bulky, for the extreme cold environment in my opinion this bag is one of the best, if not the best, on the market. Kudos to Western Mountaineering!