... ", 3", 3.5", 4", 6" 3) Connection size: 1/8"air pressure gauge1) Case: steel with bronze plate2) Dial: 1.5 ... c) Connection: brass, stainless steel d) Dial and pointer: aluminum e) Window: glass, polycarbonate7) Pressure range: vacuum, compound, 0 - 15psi - 10 ... : 1.6%-2%, 3%-2%-3% of FSD. Pressure Gauge air pressure gauge