Float switch: Switching device that activates or deactivates when the liquid is rising or sinking. Cable and weight included. A float switch is a device used as a level gauge and detects the level of liquied in a tank or enclosure. A float switch opens or closes an electrical circuit to control the flow of an electrical current to a connected device as a pump or valve. For controlling pump or valve to allow water in or out as required by the respective application. 10M cable.