Operation is based on a buoyancy principle where by a spring is loaded with weighted displacers which are heavier than the liquid under control. Immersion of the displacer in the liquid results in a buoyancy force change, producing a spring load  reduction which moves the spring there by actuating the magnetic switch which is kept inside the stem

Customized suiting to the service (fluid) and temperature.
Available in SS 304/ SS 316/ pp/ pvdf/ hdpe etc
Available with weatherproof or flameproof enclosure.