At 90" X 36", the Celsius XL is bigger than most bags on the market. Filled with SuperLoft Elite 4-channel hollow fiber insulation to keep the cold out, the Celsius XL bag comes with all the bells and whistles of a more expensive bag: 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 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 -32°C / -25°F which means it will be warm even in winter-camping situations. For an even warmer bag, you can add the TETON Sports XL Sleeping Bag Liner.