GE’s PanametricsDigitalFlowâ„¢ GM868 general-purpose flow meter measures gas flow in pipes or ducts. Innovative configurations for installation of its ultrasonic transducers meet pipe or duct size and other application-oriented requirements. This obstructionless meter has very wide rangeability, causes no pressure drop, and requires no regular maintenance. Analog and digital outputs in velocity and actual volumetric flow rate are standard.