5109.90.80.00 - Of wool fiber with an average fiber diameter of 18.5 microns or less (400)

This HTS classification, 5109.90.80.00, pertains to yarn spun from wool fibers, specifically those with an average fiber diameter measuring 18.5 microns or less. This yarn must also be presented in a format suitable for retail sale, such as skeins, balls, or hanks of a size commonly purchased by end-consumers. The classification emphasizes the fineness of the wool fiber as a key determinant, distinguishing it from yarns made from coarser wool or other animal hair.

This category stands apart from its sibling, 5109.90.90.00, which encompasses "Other" yarns of wool or fine animal hair for retail sale. The distinction lies in the specific average fiber diameter requirement of 18.5 microns or less for 5109.90.80.00. Goods classified under the sibling category would not meet this precise measurement criterion or might be composed of different types of fine animal hair not covered by this specific entry.

As this is a leaf node within the HTS structure, there are no further subcategories to introduce. The classification is definitive based on the material (wool), its average fiber diameter (18.5 microns or less), and its presentation for retail sale. Therefore, the primary focus for classification under this code is the accurate verification of these stated attributes.