The Crescent Lake uses TechLoft insulation, a polyester hollow-fiber that gives you great loft and warmth. The 2-layer offset construction (sometimes called a "bag within a bag") gives you warm and comfortable bags rated at 20, 0, and -20 degrees. A contoured hood, a self repairing #8 zipper, and 210T polyester fabrics give you the features you need in a good backpacking mummy bag. Regular (32" x 80"), and long (34" x 86") sizes are available, along with right and left hand zippers. A standard stuff sack is included.