Dwyer Mini-Master Series MMF Flowmeter, Range 0.1-1 SCFH Air, Bottom Mount Valve 1-1/2" scale flowmeter for monitoring and measuring small volume air flow in scfh 1/4" OD inlet and outlet connections for inline mounting Accuracy of + or 10% of full scale Made of styrene acrylonitrile polymer for durability and a clear view of the scale Black scale graduations are printed on an aluminum plate alongside the flow tube for distinct readings