The North Face Dolomite One Sleeping Bag is a versatile sleeping bag for a range of temperatures. Camp more comfortably with the help of synthetic Heatseeker Eco and 700-fill power-down insulation. The back features synthetic insulation, resisting compression, the midlayer utilizes down for warmth without the weight, and the top features synthetic. In one bag, layer as necessary to get a 40F, 20F, or 5F bag. The outdoors can be unpredictable, this bag means you only have to choose one.