The Chinook Infinite 15F will keep you nice and toasty down to +15 F / -9 C thanks to its state of the art PrimaLoft insulation. PrimaLoft is a fine denier, high loft filament insulation that offers maximum warmth, compressibility and sofness. The upper has one layer, the lower two. The shell is made from durable Ripstop Nylon while the lining is polyester. This is an ideal easy-care super warm sleeping bag for extended trips into the wild or camping holidays in places where the nights can get real cold.