No Batteries! This high tech rain shower head powers the LED lights using a built in hidden dynamo. The lights will automatically turn on when water pressure is turned on. The lights will dim and brighten when you lower and raise the pressure. So you can set the perfect mood, water & light. Auto Temperature Detected Light Color Change! The shower head will automatically change colors according to the temperature of the water. So you always know how the water will feel on your skin just by looking at it. - When water temperature is below 113'F lights glow BLUE. - When water temperature is between 114'F - 121'F lights glow RED. - When water temperature is over 122'F lights flash RED. Never be scalded again by entering a shower that is just too hot! Standard size. Replace your old shower head with this exciting new product. The threading is universal so it will fit any standard shower head by simply unscrewing the old one by hand and attaching the new one. A shower arm is not included. This head can be used with either wall or cieling mounter arm. Modern Stylish Design. Completely polished chrome made to match or stand out from your other bathroom fixtures. High Quality. This modern shower head is made out of solid stainless steel, not plastic, so its made to last, not just to look good.