The Sea to Summit Adaptor CoolMax Travel Liner is a sheet for your sleeping bag. You can also use the liner on its own for hot, humid nights or when you're couch surfing at your BFF's. The fabric is not only soft against the skin but wicks moisture to keep you cool through the night. Features of the Sea to Summit Adaptor CoolMax Travel Liner New Traveller shape with a pillow insert Adapts to varied temperatures and humidity Versatile sleep system: use by itself or as part of a layered system Wicks moisture for a more comfortable night's sleep Comfortable stretchy fabric Contrasting color along top edge makes it easier to find the opening Keeps sleeping bag clean Machine washable and quick drying