Add some warmth to your sleeping bag while keeping it clean with the Slumberwick Mummy Liner. Using a wicking polyester that pulls moisture and sweat away from your body while also added some warmth, you will stay comfortable while using the Slumberwick liner. The two way, 57" zipper will make getting in and out of the liner easy while the trapezoidal foot box provides space so feet remain in a natural position for more comfort.