The Western Mountaineering Puma MF offers 9 inches of loft, 36 ounces of 850 fill power down, two densely packed Interlocking draft tubes, and a full down filled collar that will keep you in warm to 25 below zero. The VBlock side baffle provides phenomenal down control which is necessary in a bag with this much loft. You get a 64 inch shoulder girth, so there's even room for layering. The MicroLite XP shell has superior breathability while being extremely water resistant. This bundle of warmth weighs in at just 3 lb 7 oz total weight.