... Spec 5CT latest edition. We supply all seamless and ERW casing pipes according to API Spec 5CT latest edition. Our ... casing are produced by the leading OCTG manufacturers in China like TPCO, Hengyang Valin, Baotou Steel, Jiangsu etc. Grades ... : H40, J55, K55, N80, L80, HC N80, C90, T95, P110, HC P110. The outer diameter of casing is ...