Casing & Tubing Casing & Tubing All the casings and tubings can be custom made and produced in standard diameters, such as 20 “, 13 3/8”, 9 5/8 “, 7”, 3½ “, 2 7/8″, 2 3/8 ” and in the quantities of P110, L80, N80, K55, J55 according to API 5 CT Standards.