... in pickling pipe and recycling acid to clean sheet metal, steel curtain and stainless steel sheet in metallurgy industry ... 5. Filter material: 304, 316L, PP, PTFE, Fluoro rubber, metal or nonmetal material, to meet different requirements.6. Standard seal ... material: nitric rubber7. Optional material: PTFE, fluoro rubber, PVDF, silicon rubber, metal voluble graphite, ring nuts, loose joints and bolts. ...