OP-B-2 is a series OP Orifice plate flowmeter, a complete flow metering package. It incorporates a stainless steel orifice plate with a unique holder or carrier ring containing metering taps and integral gasket. The series OP can be used with compatible liquids and gases. It features 0.75 line size, 0.400 bore, 0.49 beta, water capacity- 100 D.P. WC, 5.69 GPM flow, AIR CAPACITY- 100 D.P. WC, 20.21 SCFM at 14.7 PSIA, 32.44 SCFM at 20 PSIG, 60.26 SCFM at 100 PSIG, 1 LB weight. Typical applications include fluid flow rates in building water lines, boiler feedwater, cooling water, combustion or compressed air and steam flow.