Our Heat Liner provides an additional warming layer (improving the comfort temperature even up to 9 °F) and highly increases the hygiene of using a sleeping bag. It is simple and yet practical – manufactured from an ultra-thin Toray Airtastic® fabric, filled with Climashield® insulation, it weighs a mere 10.05 oz. This is a great solution both for wandering in the mountains and during ultra-marathons, where reliability and low equipment weight are key.