Each radiator/towel rail requires one valve set as illustrated and priced here.
A thermostatic valve is self-regulating, and controls the temperature of the radiator/towel rail by changing the amount, or flow, of hot water in to the radiator/towel rail. The second type of valve is a manual valve. Simply put, the user rotates or twists the valve to increase or decrease the amount of hot water coming in to the radiator/towel rail.
These copper plated valves are supplied un-lacquered. You can leave the surface to naturally tarnish over a period of use/time, or maintain the finish using a metal polish. We would recommend Autosol metal polish as being a suitable product to achieve this.