Wild country mummy sleeping bag liner description sleeping bag liners prolong the life of your sleeping bag and can be used on their own in warmer climates or add extra warmth in colder conditions the mummy shaped liner is designed to fit the same shaped sleeping bag its polycotton composition means its lightweight and quick and easy to wash and dry and comes in its own handy stuff sac specifications packed weight 240 grams fits mummy shaped sleeping bags quick and easy to w