Heat Liner + provides an additional warming layer and significantly improves hygiene when using a sleeping bag. Made from ultra-thin Toray® Airtastic fabric and filled with Climashield® insulation, it increases a bag’s rating by 12.6°F. The Heat Liner + features a zipper and a hood, allowing it to be spread out and used as a cover while traveling or sleeping in a mountain hostel. It’s an excellent solution for mountain trekking and ultra-marathons, where reliability and low equipment weight are essential.