The Celsius Regular bag has higher quality materials and construction than most bags in its price category. Filled with SuperLoft Elite 4-channel hollow fiber insulation to keep out cold, the Celsius bag comes with all the bells and whistles usually found on more expensive bags: shoulder and zipper baffles, adjustable mummy hood, interior storage pocket, and an oxford nylon compression sack to pack it away when not in use. The internal storage pocket is sized for keys, wallet, watch and other valuables. Two Celsius Regular bags zip together with left and right side zippers. See www.tetonsports.com FAQ section for info on choosing left or right zippers and zipping together. The bag is temperature rated to -18°C / 0°F which means it will be warm for all but extreme-winter camping.