The KENCO Model KEFS uses a float to determine the presence or absence of liquid in a vessel at the process connection. The float arm assembly consists of a float at one end and a magnet at the other. As the level in the vessel rises, the float rises and the magnet falls. The magnet actuates a second magnet on the other side of the pressure boundary. This second magnet causes the switch to change state.

The pressure boundary contains no seals; it is a solid stainless steel barrier that passes a magnetic field, but no liquids. It is impossible for the process liquid to enter the switch enclosure through this barrier. The electrical contacts consist of a microswitch that can be either a single-pole, Double-throw (SPDT) or Double-pole, Double-throw configuration (DPDT). The SPDT Switch is available with either a 5 Amp or 8 Amp current load. The DPDT Switch is only available with a 4 Amp current load.