Mummy Bag

A mummy bag is a type of sleeping bag designed with a tapered, body-hugging shape that resembles the outline of a mummy. This design minimizes excess space around the sleeper, which reduces the amount of air that needs to be warmed by body heat, making it more thermally efficient than rectangular sleeping bags. Mummy bags are popular among backpackers and cold-weather campers because they offer superior warmth-to-weight ratio and pack down smaller, though they provide less room to move around than traditional rectangular sleeping bags.