Over thirty years ago, Western Mountaineering began manufacturing sleeping bags. Two northern California mountaineers shared a vision and through their dedication Western Mountaineering is producing sleeping bags that are light and warm and will be comfortable for you at any event, expedition or outing. Western Mountaineering® HighLite 35 Degree 850+ Down Sleeping Bag. ExtremeLite™ shell fabric. Western Mountaineering® UltraLite Super 20 Degree 850+ Down. The Full Down Collar helps to seal in heat around your neck without adding excess bulk. Western Mountaineering® HotSac™ Vapor Barrier Liner. A VBL works by stopping heat loss from evaporative cooling. The new Hot Sac™ weighs only 4.5 ounces and is light enough to carry on day trips as an emergency bivy. Western Mountaineering® Apache Super MF 15 Degree 850+ Down Sleeping Bag. The MicroLite XP™ shell is weather resistant and yet breathable. At a total weight of 2 lbs. 1 oz.