Scully two-wire optic sensors are purpose-built for liquid petroleum product overll prevention and point level detection. They are designed to be used with the Scully Intellitrol® and ST-15 series loading rack control monitors. The sensors can also be used with the Scully IntelliCheck® II Monitor. There is no waiting for the control monitors’ permit light to go on because the sensor requires no warm up time. Overfill prevention applications include road tankers, rail cars and storage tanks.