Temperature controlled shower light. Shower light lets you know when the water is getting hot! Turn the water on and a flood of blue light shines down through the shower steam cool blue and refreshing. When the water gets hot 89° Fahrenheit 32° Celsius the LED light changes from Blue to Red letting you know that the water is hot and ready. Shower light generates its power as water flows through the eternal turbine. No batteries required. On one standard pipe plumbers tape suggested installed in minutes. Flow does not exceed 2.5 GPM at 80 psi.