A KOHLER MasterShower thermostatic valve controls the temperature and a separate volume control valve controls the flow. A simple concept that gives you total control over the shower environment. Bring a luxurious showering experience to your bathroom with the MasterShower collection. The collection's simple lever handle makes it easy to operate your shower. Pair shower trim trim with a MasterShower showerhead and Rite-Temp pressure-balancing valve, which maintains your desired water temperature during pressure fluctuations.