5509.99.60.00 - Other (607)

This HTS classification, 5509.99.60.00, pertains to yarns of synthetic staple fibers, not intended for retail sale, that do not fall into more specific categories within synthetic staple fiber yarns. Crucially, these are yarns composed *solely* of synthetic staple fibers or mixed predominantly with other synthetic staple fibers, but not those containing significant amounts of artificial staple fibers. The absence of a "sewing thread" designation indicates these are generally intended for industrial or manufacturing purposes beyond direct consumer use.

This category serves as a residual classification for synthetic staple fiber yarns when other specific subheadings are not applicable. It is distinguished from sibling categories which might address blends with artificial staple fibers or specific yarn constructions not present here. The "Other" designation signifies that these yarns do not fit into pre-defined, more granular classifications within the synthetic staple fiber yarn group at this level.

As a leaf node, this classification does not have further subcategories. Therefore, the practical classification criteria for goods falling under 5509.99.60.00 rely on the fundamental definition of synthetic staple fiber yarn, ensuring it is not put up for retail sale and does not contain significant proportions of artificial staple fibers, and that it is not otherwise specifically provided for in preceding subheadings of 5509. For example, this would encompass yarns made from polyester, nylon, or acrylic staple fibers, spun into yarn form, and intended for use in weaving, knitting, or other textile manufacturing processes, provided they are not sold directly to consumers in their yarn form and do not meet the criteria for other specific subheadings.