NEMO says: "With a unique Spoon(TM) shape adding room at the elbows and knees, the Rave(TM) is a three-season women's down backpacking bag designed for side sleepers and allows you to shift positions throughout the night. This popular bag is loaded with features, including Thermo Gills(TM) that help regulate temperature during the night, Blanket Fold(TM) that provides tucked-in comfort, and a waterproof / breathable footbox to withstand tent condensation."