Designed for those gram-counting backpackers searching for the lightest gear with comfort in mind, the Torchlight UL Mummy bags feature all of the bells and whistles found in our Torchlight series. Two expandable panels from shoulders to footbox, increasing sleep space up to 10 extra inches! Depending on your sleep style and body shape, you can adjust the bag for customized comfort. This bag is insulated with 850 fill power DownTek water-repellent down, and baffle construction that provides more efficient heat distribution with zero heat loss, even when the bag is expanded.