A product developed to support a clean energy society friendly to the global environment. This “No Throwaway” rechargeable warmer (kairo) can be used over and over and turned on and off anytime. Today, 1.4 billion disposable warmers are disposed annually. In contrast, one rechargeable kairo can be repeatedly used 1,000 times using 2 size AA “eneloop” nickel-metal hydride rechargeable batteries. Aluminum material is used for all sides of the body. Hold it in the palms of your hands and enjoy its warmth to the tips of your fingers. A PTC heater and microcomputer enable high-precision temperature control preventing low-temperature burns.