This sheet is a sleep sack that is perfect for any kind of travel. It is lightweight and packs very small. When using this sheet, it is easy to protect your sleeping bag, by having to only wash the sheet. This prevents the wearing of the sleeping bag. It also features a pillow pocket. This sheet is a sleep sack that is perfect for any kind of travel. It is lightweight and packs very small. Woven with a grid-like structure of strong silk threads, Ripstop Silk is more durable and resistant to tearing than regular silk - an innovative fabric developed by COCOON.