... For general use, black steel case, plastic rotating window, brass internal and connection. Product Name:iron case Pressure Gauge 1) Dial size: ... bsp (g, pf), bspt (zg, pt)4) Case material: black steel, plastic, chrome plated steel, stainless steel,iron5) Material of connection ... : 3% - 2% - 3% , ±2.5%8)Lip Material: Plastic, plastic dial face, glass dial face9)Bourdon Tube: brass, phosphor bronze ...