A MummyLiner is an extremely lightweight, mummy-shaped inner sleeping bag. It can be used as a comfortable, skin-friendly inner sleeping bag, to protect the sleeping bag from dirt, to enhance the thermal performance of your sleeping bag, and as a sleeping bag in warm and tropical climates. Merino sheep provide particularly fine, non-itchy, high-quality wool. Merino wool is soft, lightweight, elastic, and has excellent thermal performance and temperature regulation. Air can circulate in the natural cavities of the wool fiber, promoting skin breathability and effectively wicking away moisture. Furthermore, Merino wool remains odor-neutral and germ-free even after prolonged use.