Compact mechanical switch offers a combination of reliable solid state electronics and a sealed float switch. False start prevention, no mercury, high impact plastic and encapsulated electronics adds up to dependability. Activates pump at 2" water level, deactivates pump at 3/4" water level. The switch is designed to attach to the SPX FLOW Johnson Pump Cartridge bilge pumps. When attaching to other SPX FLOW Johnson Pump bilge pumps, use the adapter provided. This magnetic float switch is 12 volts.