No battery is needed When water flows down, the LED will light instantly and automatically.When water temperature is below 25 centigrade, green color will show automatically When water temperature is between 26~35C, blue color will show automatically When water temperature is between 36~45C, red

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