FO Series 5134 operates with visible light to provide point level control or detect leaks, making it intrinsically safe and suitable for use with flammable or explosive fluids. Sensor measures 1/4 in. dia and is made of noncontaminating, noncorrosive materials, including Teflon, quartz, Udel, and Type 316 stainless steel. Sensor works with Kontec Series 5135 liquid level controller, which provides pulse modulated light source, signal amplifier, and dual 300 mA output transistors. Single-turn potentiometer on controller adjusts sensitivity.