The Big Agnes Lost Ranger Ul 3N1 0 Sleeping Bag is a versatile sleeping bag for a variety of ventures into the backcountry. One system, three ways to use it. This bag features an inner bag and outer bag, so you can use each separately or combine them for one toasty package. The inner bag is mummy-style, rated at 20°F, the outer bag is blanket-style, rated at 45°F, and the combination of the two rates at 0°F. The 850 fill DownTek insulation is warm, compressible, and water-resistant. Features include two-way zippers to help with temperature control, a pillow pocket, hand pockets (in the outer bag), plus a Pad Cinch System to connect your bag to your sleeping pad. Sleep well out there, in a wide range of temperatures.