304 stainless steel case bottom brass connection oil composing:glycerine, silicone oil diameter:1.5 ... ",2",2.5",3",4",6". Bottom Brass Connection Stainless Steel Oil Filled Pressure Gauge 1. Diameter: 1 ... 8",1/2",NPT,BSPT,BSP;6.Connection: bottom connection, center back male connection;7.Range:0~10,000psi;8.Scale: ... : 2.5%,1.6%,1%. Bottom Brass Connection Stainless Steel Oil Filled Pressure Gauge