Heat. Health-keeping constant temperature blanket is a kind of small household appliances to keep warm. The main functions of Tian Fang 1 constant temperature blanket are heating and heat preservation. The advantages of this constant temperature blanket are that it does not need electricity to sleep, is super safe, has no electromagnetic radiation and does not catch fire. When in use, charge and store energy half an hour in advance, then automatically cut off the power supply, slowly release heat, and keep the bed at a constant temperature all night.