Denali, Aconcagua, Himalaya... mountaineering at its extreme. These are places where mistakes cannot be made and so the Bison Super is often the bag of choice. DryLoft fabric makes this bag impervious to the elements while remaining lightweight and very compressible. Crammed with 42 ounces of 850 fill power down, this bag has 10 abundant inches of heat trapping loft. Huge V-Block Side Baffles and horizontal baffles across your chest keep the down fill in place where it counts. Double Interlocking Draft Tubes and a down filled DryLoft collar seal in heat and security even while winds pound your tent. The massive hood is not only well filled but is made entirely with DryLoft fabric and has a large integral hood ruff to seal your face from the elements. The Bison Super is the crowning jewel of Western Mountaineerings bomber bag line, and demonstrates their commitment to innovation and quality. This life saving bundle weighs a scant 4 lbs 7 oz.