Hog Wild Shower Light Alerts users when water temperature has reached 89 degrees F; no guesswork and no jumping into a too cold shower Blue light shines when cooler waters are running; once water heats, light color changes to red No batteries required; rushing water powers a tiny internal generator Built-in flow regulator limits water flow to 2.5 gpm or 80 PSI Fits standard shower pipes and installs in minutes with no special tools; great way to get kids showering on their own