What Our Gearhead(R) Experts Are Saying:"This sleeping bag is a lifesaver in frigid temperatures. I've used it on winter trips in the Scandinavian mountains and found it keeps me warm well below freezing, especially with the breathable and waterproof Stormshield fabric keeping moisture out. It's the perfect bag for extreme winter expeditions."For those of us who venture into the world's harshest winter environments, the Western Mountaineering Puma Stormshield delivers the ultimate level of warmth and protection. This unique winter sleeping bag is crafted with Stormshield-a windproof, waterproof, and vapor-permeable outer material designed to keep the high-loft 850-fill goose down dry, even in the coldest, most unforgiving settings. With an impressive comfort rating down to -25degF, the Puma Stormshield is a trusted companion for cold-weather expeditions and single-wall tent bivouacs where every ounce of warmth counts. The bag's three-dimensional, fully insulated thermal collar and overlapping zipper covers shield from the elements, ensuring that precious body heat is conserved even in severe conditions. Inside, the roomy foot box and wide hood lined with durable taffeta provide comfort and durability, making space for extra clothing or gear without compromising the loft. Whether we're in snow bivouacs or enduring biting winds, this bag's unique prototype design proves Western Mountaineering's commitment to unparalleled quality in extreme winter sleeping gear.