American Standard R523R523 1/2-Inch 2-Handle Shower Theromstat Rough Valve with Built-In-3-Way Diverter Brass Casting: Highest quality faucet material for durability and long life Built-in Diverter: Allows user to choose between 2 or 3 separate shower outlets Wax Thermostatic Unit: Permits shuttle valve to move between the hot and cold seats to maintain the pre-selected constant water temperature Back to Back Capable: Hot and cold can be reversed Spring-Loaded Check Valves