Valves fixed to the inlets and outlets of radiators to control the flow of the heating medium.
Open/Closed simple control. May have wedge or disk valve, angle or straight-through ports, and operating handle or removable key, and used for balancing or temperature control.
Regulating Valve used for proportioning or balancing flow to radiators in a heating system.
Double Regulating Valve. A combination of both previous types and used to preset the maximum flow through the radiator and also temperature.