CS GOST RUSSIAN STANDARD FLANGE standard:gost size:1/2"-24" ... flanges and the pipefittings collection in th emost standard and material. FLANGE: WELDING NECK ,SLIP ON ,BLIND ,PLATE,THREADED,LAPPED ,SCREWDE ... :PN 6,PN 16,PN 10,PN 25,PN40,PN63materail:CS CT20,16Mn,SS304/304L,316/316L COATING:RUST PROOF OIL ...