... 1/2"~20" 2.Casing Grade: H40, J55, K55, N80, M65, L80, C90 3.Casing Length: R1,R2, R3 API 5CT Casing 1 ... .Casing Sizes: OD 4-1/2"~20" 2.Casing Grade: H40, J55, ... Coupling. Our factory manufacture Casing, Tubing: According to API SPEC 5CT Casing . Casing Steel grade: ... . Range Tubing: From 2-3/8"to 4-1/2"(EUE/NU) Casing: From 4-1/2" to 20", Casing Threads: ... P110 API 4 1/2"Oil casing