This sleeping bag liner feels like a luxury sheet, is easy to insert in your bag, and quickly comes out for machine wash. Protect your bag from dirty feet and campfire smoke smells, while improving your comfort. Liners extend the life of your sleeping bag, and they are a must-have for multi-day trips or when parents and kids all pile into the huge Mammoth sleeping bag. Liners make cleanup after camp much easier, and this is one of the best liners out there for the price. This liner will improve the temperature rating of your sleeping bag by about ten Degrees.