The following is a LED shower light, which may install to standard shower pipes. The shower measures approximately 4 inches in diameter and is powered by an internal turbine and doesn't require batteries. It also includes a flow regulator that limits maximum water flow to 2.5 gallons per minute at 80 psi. Turn the shower on and a blue light tells you the water is cold. A red light means it has warmed to 89°F. The light goes for $39.99.