Tubing is pipe used for the transportation of crude oil and natural gas from an oil or gas layer to the surface after drilling is complete. It is made to withstand the pressure generated from the extraction process. Tubing is manufactured in the same way as casing, except that an additional process known as "upsetting" is applied to thicken the pipes.

API casing, seamless or ERW casing size from 4-1/2" to13-3/8" and also large size ERW 16", 18-5/8",