1¡éas the built-in device generating electricity without the battery and any other power connets to water, led will emit the light. When water flows down, the led will light instantly an automatically; When water temperature is, green color will show automatically ; ;¡éwhen water temperature is between 3 blue color will show automatically; C¡éwhen water temperature is between red color will show automatically; D¡éwhen water temperature is above red color will flash immediately. 3. This item will change its color by detecting water temperature. Color box packing:1 piece inner each color box 36 piece outer each carton
