100% Chinese Silk is a natural fibre giving great warmth for weight, one of the lightest natural fibres. Why choose silk? Down bags are more time consuming to wash and dry than synthetics and the use of a silk liner will help to avoid the need to clean your bag. A silk liner adds 2C of warmth to your sleeping bag. Silk sleeping bag liners are extremely light weight, have a small pack size and are easily washed making them perfect to carry on lightweight backpacking trips. Finally silk is luxurious to sleep in!