JOI does not use batteries, solar, or wall power to create its own light. JOI uses thermoelectric technology to transform the energy of a tea light candle into enough light to illuminate your night. Within minutes JOI begins to convert the heat of the candle into more than 18 times the light generated by the tea light alone. Designed to be a contemporary centerpiece with a style that appeals to all, JOI gives you a unique and useful light source indoors and out.