Dwyer Instruments Inc. has introduced an optical level switch unit that indicates via bright green and red LEDs the presence or absence of fluid. The OLS optical level control has no moving parts and can be mounted in a vertical or horizontal position by means of a 1/2-in. threaded process connection. Overall length is 13/4 in., maximum pressure is 200 psig, maximum temperature is 200 °F and weight is 2.5 oz. It is suited for food and beverage systems, hydraulic reservoirs and pharmaceutical plants.