No battery is needed2. When water flows down, the LED will light instantly and automatically.A. When water temperature is below 25 centigrade, green color will show automaticallyB. When water temperature is between 26~35C, blue color will show automaticallyC. When water temperature is between 36~45C, red color will show automaticallyD.
When water temperature is above 46C, red and blue color will flash
immediately and simultaneously, which warns you should be careful.3. This item will change its color by detecting water temperature.Product specification:1. Temperature detectable with three colors2. No battery needed, Embedded Dynamo3. LED lifespan: 8000-10000hours.