Dwyer Visi-Float Series VFC Flowmeter, Female Fittings, 5" Scale Length, Range 2.5-25 SCFM Air, 1" Female NPT Process Connection 5" scale flowmeter with 1" female NPT connections for inline monitoring and measuring air flow Accuracy of + or  2% of full scale for precise readings Stainless steel guide rod and large diameter float enable stable readings Made of solid acrylic plastic to resist breakage and provide a clear view of the scale Black scale graduations for distinct readings