Sea To Summit's Coolmax Liner is multi purpose; it can be used by itself or as part of a layered system. You can use it as a liner for a sleeping bag or as an extra layer to add to your bedding. Either way it is a great product. The liner *Adapts to varied temperatures & humidity *Wicks moisture; keeps you dry *Regulates your sleep comfort *Keeps sleeping bag clean *Comfortable and stretchy fabric *Machine washable & quick drying