... type,flange type. Sizes:DN50~DN600. check valve,swing type,flange type.Design & manufacture standard: API6D, ANSI/ASME ... B16.25.Socket-welding dimensions: ANSI/ASME B16.11.Inspection & test standard: API6D, API598.Pressure: 150Lb, 300Lb, 600Lb, 900Lb or PN ... , CF8(304), CF8M(316), CF3(304L), CF3M(316L), etc. check valve