1. No battery needed;      
2. When water flows down, the LED will light instantly and automatically;
A. When water temperature is ??30C, Green color will show automatically;  
B. When water temperature is between 31C~41C, Blue color will show automatically;      
C. When water temperature is between 42C~45C, Purple color will show automatically;      
D. When water temperature is above 45C, Red color will show automaticlly      
3. This item will change its color by detecting water temperature.