5407.61.21.00 - Wholly of polyester, of single yarns meas- uring not less than 75 decitex but not more than 80 decitex, having 24 filaments per yarn and with a twist of 900 or more turns per meter (619)

This HTS classification, 5407.61.21.00, specifically covers woven fabrics that are composed entirely of polyester filament yarns. These yarns possess distinct physical characteristics: they must measure between 75 and 80 decitex, contain precisely 24 filaments, and exhibit a twist of 900 or more turns per meter. These criteria ensure a particular type of fabric construction and hand, differentiating them from other polyester woven fabrics.

Within the broader category of "Containing 85 percent or more by weight of non-textured polyester filaments," this subcategory is distinguished by the specific yarn specifications outlined. Its sibling category, 5407.61.29.00, represents "Other" woven fabrics within this group, meaning it encompasses fabrics that do not meet the precise decitex, filament count, or twist requirements of 5407.61.21.00. This emphasizes that the classification hinges on the precise technical specifications of the polyester yarns used.

As this is a leaf node within the HTS structure, there are no further subcategories under 5407.61.21.00. Therefore, the focus remains on the exact fulfillment of the yarn characteristics described. Importers and exporters should meticulously verify the decitex, filament count, and twist per meter of the polyester yarns to ensure accurate classification of their woven fabrics within this specific code.