The Float Switch FS-40 has been designed to be used with bilge pumps rated up to 10A. The FS-40 activates or deactivates the bilge pump, depending on the water level. Namely, when the water level rises, it forces the float upwards, which switches on the bilge pump. By installing the float switch, there is no need to monitor the water level and switch the pump on or off manually. A very important feature is that you can test the smooth operation of the switch at any time, just by using the test button. The Float Switch FS-40 is made of tough ABS for long life. Voltage: 12V/24V DC