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