7304.29.31.10 - Having a wall thickness less than 12.7 mm

This HTS classification, 7304.29.31.10, specifically identifies seamless tubes and pipes made of iron or steel that are intended for use in drilling for oil or gas. Within this subcategory, it further narrows down to casing, which is a type of pipe used to line oil and gas wells. The defining characteristic for this specific code is that the casing is constructed from "other alloy steel" (not specified by specific alloying elements at this level) and is threaded or coupled for connection.

The crucial differentiating factor for this category is its specified wall thickness. HTS 7304.29.31.10 covers casing where the wall thickness is **less than 12.7 mm**. This is in direct contrast to its sibling category, 7304.29.31.20, which encompasses casing of the same material and purpose but with a wall thickness of **12.7 mm or more**. Both categories share the criteria of being seamless, for oil and gas drilling, of other alloy steel, threaded or coupled, and having an outside diameter less than 215.9 mm, making wall thickness the sole determinant for distinguishing between them.

As this is a leaf node in the HTS classification, there are no further subdivisions. Therefore, the focus for classification under 7304.29.31.10 rests entirely on verifying that the article meets all preceding criteria: seamless construction, use in oil or gas drilling, being casing of other alloy steel, threaded or coupled, having an outside diameter less than 215.9 mm, and crucially, possessing a wall thickness strictly below 12.7 mm.