5509.51.30.00 - Single yarn (607)

This HTS category, 5509.51.30.00, specifically covers single yarns made from synthetic staple fibers, primarily composed of polyester, that are mixed mainly or solely with artificial staple fibers. Crucially, these yarns are not intended for retail sale and are presented in a single strand construction. Examples include bulked yarns or spun-dyed yarns made from polyester and rayon or other artificial staple fibers, intended for industrial use in weaving, knitting, or other textile manufacturing processes.

The distinction between this category and its sibling, 5509.51.60.00, lies in the yarn's construction. While both are derived from polyester staple fibers mixed with artificial staple fibers, this category exclusively covers *single* yarns. The sibling category, on the other hand, pertains to yarns that have been twisted together to form *multiple (folded)* or *cabled* yarns. Therefore, the number of individual strands making up the yarn is the key differentiator.

As this is a leaf node within the HTS classification, there are no further subcategories. The classification is considered final at this level, meaning the described goods meet all the criteria to be definitively placed here based on their material composition (polyester staple fiber mixed with artificial staple fiber), construction (single yarn), and end-use presentation (not for retail sale).