... of originChinaGradeQ195,Q215,Q235,Q345,X42,X60,X65,X70,GR.A,GR.BSpecification1.Outer Dianeter:21.3mm-609.6mm 2.Wall ... DIN GB9711.1-1997A500API 5LST33DIN2391 GB/T3091A252API5CTST35 GB/T3094A53Gr.AAPI LINE PIPEST38 GB9948-88A53Gr.B ST45 GB8162-1999A795 ST52 CertificatesISO , API ...