... diameter:1.5",2",2.5",3",4",6". Bottom Brass Connection Stainless Steel Oil Filled Pressure Gauge 1. Diameter: 1 ½", 2 ... ", 2 ½ ",3",4",6";2.Case: 304 stainless steel;3.Window:polycarbonate;4.Internal: brass, stainless steel;5.Inlet thread:1/8", 1 ... , silicone oil;10.Accuracy: 2.5%,1.6%,1%. Bottom Brass Connection Stainless Steel Oil Filled Pressure Gauge