Single Elastomeric Filament Yarn, Untwisted or Low-Twist

Bare elastomeric yarn — a single strand of elastomeric polymer with no covering fiber — classifies under heading 540244 when untwisted or with low twist. Once that elastomeric core is wrapped or covered with another yarn (nylon, polyester, cotton), the product typically reclassifies based on the covering fiber or as a gimped yarn under a different heading. Importers should verify whether the yarn arrives bare or covered, as the two forms carry different HTS codes and potentially different duty rates.

South Korea hosts major elastomeric fiber producers and has well-established synthetic fiber manufacturing infrastructure. Imports from South Korea may be eligible for preferential duty treatment under the US-Korea Free Trade Agreement (KORUS), subject to applicable rules of origin. Importers should confirm origin qualification with a licensed customs broker before claiming KORUS preference.