Description Smith Equipment Replacement Pressure Gauges are manufactured in accordance with Smiths' rigid quality standards. One-piece polycarbonate crystal is shatter resistant and has a protective lip to prevent damage to the face. All gauges feature precision watch-type movements for optimum accuracy. Gauges are supplied in convenient Slider-Pak packaging for an attractive display, allowing removal and inspection of the product without damage to the packaging. 2(51mm) and 2-1/2 (64mm) Gauges U.L. Listed. Watch-type precision movement for optimum accuracy. Fits all major brands of gas pressure regulators using 1/4" FNPT gauge inlet threads. High visibility cupped steel face. PSI/Bar pressure gauges and CFH/LPM flow gauges Preferred design with 1/4 turn crystal ring and brass case.