The Rule-Mate series of Automated Bilge Pumps feature a pump and a non-mercury float switch in a single, compact housing. When the float rises, the bilge pump turns on. There is no on/off cycling and therefore, no power use until the bilge pump comes on. The bilge pump remains on until the float drops and the pump senses no load against the impeller. Activates when the water level reaches 2 1/8".