304 stainless steel case bottom brass connection oil composing:glycerine, silicone oil diameter: ... 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", 1/4 ... ;10.Accuracy: 2.5%,1.6%,1%. Bottom Brass Connection Stainless Steel Oil Filled Pressure Gauge