5402.52.10.00 - Wholly of polyester, measuring not less than 75 decitex but not more than 80 decitex, and having 24 filaments per yarn (606)

This classification, HTS Code 5402.52.10.00, specifically covers single yarns of polyester, not put up for retail sale, characterized by a twist exceeding 50 turns per meter. The defining features are that these yarns are wholly of polyester, measure between 75 and 80 decitex, and consist of exactly 24 filaments. This precise combination of material, decitex range, filament count, and twist is crucial for its accurate classification.

This specific subcategory is distinguished from its sibling, 5402.52.90.00, by the explicit requirement of 24 filaments per yarn. The sibling category encompasses other single polyester yarns with the same twist and decitex range, but without the fixed 24-filament constraint. Therefore, while both fall under "Other yarn, single, with a twist exceeding 50 turns/m: Of polyesters," the addition of the filament count criterion narrows the scope of 5402.52.10.00.

As this is a leaf node within the HTS, there are no further subcategories. Classification at this level is determined by the precise physical characteristics outlined in the description. Importers and exporters should ensure that their polyester yarns meet all criteria, including the specific decitex range (75-80 decitex) and the exact filament count (24 filaments), to correctly assign this HTS code.