The Electric Warmer is storage heater and it is rechargeable. Only charged in 5 minutes, the warmer can accumulate heat for 3 hours in return. The firebrick contained in the heater gives the warmer incredible period of use. FEATURES： 1. To keep warm in your bed, your cold feet and hands or even your cup. 2. To relieve aches in your lumbar, knees, shoulders, etc.