The showerhead handle connects directly into your shower pipe. It gives you a unique fun and soothing experience. When water flows down, the LED will light instantly and automatically, even though no other lighting fixtures need. The change of LED color will be subject to the temperature of water, which is more modern and humanistic. When water temperature is ≤ 30 ℃ , green color will show automatically. When water temperature is 33 -41 ℃ , bluecolor will show automatically. When water temperature is 42 -45 ℃ , red color will show automatically. When water temperature is above 46 ℃ , red color will flash immediately to warn the high temperature..