The Clearwater uses MicroX insulation, a relatively new insulation for sleeping bags that has a tremendous weight-to-warmth ratio that allows you to have an ultralight and extremely compact bag. The 2-layer offset construction gives you a warm and comfortable bag rated at 20 or 35 degrees. A contoured hood, a self repairing #8 YKK zipper, and a 210T nylon ripstop outer give you the features you need in a good backpacking mummy bag.