1000W Hydroponics HPS Relay Ballast quiet,long lasting reliable quality,suitable for the high-quality illuminat 1000W HPS Relay Ballast Relay ballast:Relay Ballast works 2 lamps that great for 2 rooms for 2 different bloom stage cycles for 12 hours each. For example: Lamp A in the 1st room will automatically turn off after 12 hours and switched to lamp B in the 2nd room for 12 hours. Instructions ...