Teledyne Hastings Instruments” HFM-I-400 Series linear mass flowmeter is designed for measuring medium-to-high gas flows. The linearity of the laminar flow element allows for accurate measurements on the same instrument when changing between gases such as Nitrogen, Hydrogen, Ethylene, Propane, and Methane. Six gases are standard, and up to eight gases can be customized. Measurement is available on both the digital and analog output.