This two-handle thermostatic mixing valve allows you to select the water temperature and volume for your showerhead and body/side sprays. The lever handle controls the temperature and the cross handle is the on/off volume control. Once set, the temperature remains constant even if the water pressure changes, like when someone flushes a toilet.Brass Casting: Highest quality faucet material for durability & long life.Wax Thermostatic Unit: Permits shuttle valve to move between the hot and cold seats to maintain the pre-selected constant water temperature.Adjustable Hot Limit Safety Stop: Limits the amount of hot water allowed to mix with cold. Reduces the risk of accidental scalding. Maximum water temperature limit may be reduced to 104 or 109 degrees Fahrenheit.