Every radiator will require a pair of radiator valves, be it straight angled or double angled. Straight radiator valves are for pipework going straight up to the connection point for example straight up from the floor. Angled and double angled valves are for radiators with pipework coming up or out to the radiator at 90 degrees, such as concealed pipework that comes out of the wall and up at a right angle. You can also choose from thermostatic or manual. Manual valves are on / off only, thermostatic allows temperature control.