The lightweight and breathable Cocoon Egyptian Cotton Mummy Liner adds comfort to your sleep and lifespan to your sleeping bag. Cocoon made this liner with soft and easy-to-wash Egyptian cotton to help you sleep clean and comfortable wherever your travels take you. The Egyptian Cotton Liner adds warmth to your mummy bag on cold nights, and breathes well to allow moisture to evaporate quickly, cooling you down in hot and humid places. It also greatly extends the life of your sleeping bag by protecting it from harmful dirt and oils. At just over seven ounces, even the thought of it makes your pack seem lighter.