Johnson electronic float switch. Vent capped to prevent false starts. Electronics are sealed in epoxy and high-impact plastic. Model number: 36252. Operates on 24 volts, 10 amps. Dimensions: 3-1/4" X 1-1/2" X 3".

Digital technology uses mirus field effect detector cells producing micro-electrical fields to detect disruptions caused by water and fluids Cells are totally sealed and never contact water They will not corrode and are not affected by oil or foreign debris No moving parts, totally sealed solid state electronics Environmentally sensitive, no mercury or exposed sensors Activates at 2" fluid level and deactivates at 3/4" fluid level A 3 second delay prevents false starts Weight: .1 lb

ABS plastic for corrosion resistance. 
Comes with a three-way switch for auto/manual modes. 
Equipped with a 20 amp circuit breaker.