For all pumps up to 20 amps. No mercury, no moving parts. For all pumps up to 20 amps (All listed bilge pumps) - 12v, 24v - Marine. New digital technology uses the patented Mirus field effect detector cells producing micro-electric fields that detect disruptions caused by water and other fluids. Detector cells are totally sealed and are never in contact with the water, will not corrode and are not affected by oil or foreign debris. No moving parts Totally sealed solid state electronics and field detectors No mercury and no exposed sensors eliminate corrosions possibilities and makes it environmentally sensitive. Activates at a 50mm (2") fluid level and deactivates at a 20mm (3/4") fluid level. A three second delay prevents false starts.