5509.91Subheading
Yarn; (not sewing thread), of synthetic staple fibres, mixed mainly or solely with wool or fine animal hair, n.e.c. in heading no. 5509, not put up for retail sale
Section XI — Textiles and textile articles
This is a 6-digit subheading — the most specific level of the international HS. Country tariff schedules extend it further; the US tariff lines (HTS) below refine it to 8–10 digits for duty purposes.
US tariff lines for this subheading are not in the bundled starter dataset yet — the full HTS schedule is coming soon. You can still search by code in the tariff simulator.