When water flows down, the LED will light instantly and automatically. When water temperature is ≤32 celsius Green color will show automatically. When water temperature is between 33~41 celsius Blue color will show automatically. When water temperature is between 42-45 celsius Red color will show automatically. When water temperature is above 46 celsius Red color will flash automatically Color light turn on automatically Temperature detectable for child and elderly safety No batteries require Easy Installation, Fix for your existing hose
