Check the listing for details. FEM-03A2 Gear Flow Sensor/Transmitter, Used. Condition: Used. Listed at 425.00 USD. FEM-03A2 Gear Flow Sensor/Transmitter is a used product designed to measure the flow of liquids in hydraulic, pneumatic, and plumbing systems. It is manufactured by FEM, a company specializing in flow control solutions. The sensor/transmitter is capable of accurately measuring the flow rate of liquids and transmitting the data to a control system. It is ideal for use in industrial applications that require precise flow control.