CSA approved for use in hazardous locations, the intrinsically safe ultrasonic liquid level switch provides high or low liquid level detection of chemical, solvent or low viscosity petroleum based liquids with a 1A relay output. Media examples include hydrochloric acid, acetone and diesel fuel oil. The submersible PP or PFA level switch sensor is universally mounted through the tank wall or inside the tank, and connected to a PLC or relay controller.