Dwyer Rate-Master Flowmeter, RMA-1-SSV, 4% Acc, .05-.5 SCFH air, SS Valve, PC Body 2" scale flowmeter with 1/8" female NPT connections for inline monitoring and measuring air flow Accuracy of + or  4% of full scale Integral flow guide stabilizes the float throughout the range for consistent readings Made of injection molded polycarbonate around a precision tapered pin to maintain calibration, resist breakage, and provide a clear view of the scale Black scale graduations are marked along both sides of the flow tube for distinct readings