5509.99 - Other:

This category, HTS 5509.99, encompasses synthetic staple fiber yarns, not intended for retail sale, that are not specifically mixed with wool, fine animal hair, cotton, or artificial staple fibers. These yarns are derived from man-made staple fibers, meaning they are produced from short, discontinuous lengths of synthetic materials, rather than continuous filaments. The key differentiator for this classification is the absence of significant proportions of other specified fibers that would place the yarn into sibling categories.

Unlike HTS 5509.91 (mixed mainly with wool or fine animal hair) and HTS 5509.92 (mixed mainly with cotton), HTS 5509.99 applies to yarns where the primary synthetic staple fiber component is not predominantly blended with these natural fibers. It also excludes yarns primarily mixed with artificial staple fibers, which fall under a separate, more specific subdivision.

Within this broad category, a further subdivision exists to distinguish between different compositions. The primary subcategory, HTS 5509.99.60.00, addresses "Other" yarns. This implies that even within the "other" classification, there can be nuances regarding the specific blend of synthetic staple fibers or the presence of minor amounts of other materials not constituting a primary mix.