7304.29.10 - Threaded or coupled

This HTS category, 7304.29.10, specifically covers casing made of iron or nonalloy steel, which is a type of seamless tube or pipe used in drilling for oil or gas. The defining characteristic of this subcategory is that the casing is **threaded or coupled**. This means it is prepared with connecting mechanisms on its ends to facilitate assembly and ensure secure connections in the challenging downhole environment of oil and gas extraction.

Within the broader classification of "Casing, tubing and drill pipe, of a kind used in drilling for oil or gas," this subcategory is distinguished from its sibling, 7304.29.20, by the presence of threaded or coupled ends. The sibling category likely encompasses casing that is not prepared in this manner, potentially being prepared for welding or other joining methods after installation.

The subcategories within 7304.29.10 further refine the classification based on the physical dimension of the casing's outside diameter. These subdivisions include categories for casing with outside diameters less than 215.9 mm, between 215.9 mm and 285.8 mm, between 285.8 mm and 406.4 mm, and exceeding 406.4 mm. This precise dimensional breakdown is crucial for accurate classification and is often driven by industry standards and the specific requirements of different drilling operations.