Reliable and maintenance-free tank sensors. Very easy to assemble. KUS's design provides reliable level control, even under difficult conditions. The S-3 sensor is stainless, insulated and 2-pole - it prevents voltage in the tank and corrosion. Works in both the water and fuel tanks. 1 1/4" thread. KUS comes from one of the world's largest manufacturers of sensors and instruments for the marine industry. Among other things, the factory manufactures the Wema instruments and KUS is 100% compatible with Wema.