This is a Proffesional Contactor and not a Relay Sentinel 4 Way Contactor CS4 is a control unit with IMO relay and a Grasslin precision timer installed as standard. Sentinel CS4 is built into a robust powder coated metal enclosure but with a compact design.] The CS4 is designed to be used with 4 x 600W lights or the equivalent wattage. It also has individually switchable sockets fitted with illumination(only when lights are on). This contactor is easily wall or grow tent mountable for easy use. The Sentinel CS4 is manufactured in the UK.