The MLC-4 and MLC-4a Master Lighting Controllers are the best devices for controlling up to four HID lights from one time-clock or controller. You run 30 amp, 240 volt power into the MLC-4, and all of the outlets are controlled by one 120 volt "trigger cable". You can plug the "trigger cable" into a standard 24 hour timer or lighting controller. The MLC-4 features four standard 240 volt style (NEMA 6-15) outlets, which your ballasts are plugged into. The MLC-4a uses 120 volt style (NEMA 5-15) outlets which allows for running your ballasts at 240 volts without having to change out your ballast power cords. An integrated timer option is available which replaces the "trigger cable", allowing you to control your MLC with the built-in time clock. The MLC-4's are rated for 30 amps @ 240 volts.