The Irritrol SR-1 Pump Start Relay is designed for starting a pump to supply water pressure and flow to the sprinkler system or for switching for landscape lighting transformers. It is the perfect add-on to the Irritrol PC-Controller if you would like to control your outdoor lighting. It is used with irrigation pumps when the Irrigation Clock Control calls for an "on cycle" the pump start relay converts the 24VAC low voltage from your controller to energize the pump with 120VAC or 240VAC line voltage. It comes enclosed in a weather resistant case for outdoor protection.