Liroyal 3-color Water Glow LED Faucet Light Temperature Sensor,Pack of 2 This little device fits on most taps and lights up a set of LEDs when you turn on the tap. Transforming the stream of water into a beautiful waterfall of light. The sensitive faucet light will change colors according to the temperature of water. The color's change remind you the water's temperature. Water glows Red when water is Hot (temperature above 44C). Water glows Green when water is Warm (temperature is 32C - 43C). Water glows Blue when water is Cold (temperature below 31C). No batteries and external power supply, it will illuminate after water flows down.