... 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 ... Oil composing:glyceine, silicone oil;10.Accuracy: 2.5%,1.6%,1%. Bottom Brass Connection Stainless Steel Oil Filled Pressure Gauge