Lifeventure Mummy Silk Sleeping Bag Liners are manufactured from 100% silk. These luxurious silk sleepers are compact, light & comfortable to use. A silk sleeper can be used on its own as an ultralight sleeping bag in warm climates or as a thermal liner to a sleeping bag during the winter months or in colder climates. The silk sleepers have the added benefit of being treated with Lifeventure EX