The Rab Hooded Vapour Barrier Sleeping Bag Liner is an ultralight option that prevents your sweat from seeping into the sleeping bag overnight, making you colder in the process. So light it’s transparent, the liner’s PU-coated sil-nylon fabric offers reliable water-resistant protection against light moisture. Rab sized the liner to fit inside any sleeping bag, and the contoured hood cinches snugly around your head for comfier coverage in windier conditions.