High tenacity is generally defined by a minimum breaking tenacity expressed in centinewtons per tex (cN/tex), with the specific threshold varying by fiber type in the applicable tariff schedule notes. For polyester, the threshold is typically higher than for nylon. Importers should obtain tensile strength test reports from the manufacturer — ideally referencing ASTM or ISO test methods — to substantiate the high-tenacity classification if questioned by CBP.

Antidumping and countervailing duty orders have been applied to high-tenacity polyester yarn from certain countries in past proceedings. Importers should conduct a current AD/CVD order search through the USITC and CBP databases before finalizing sourcing decisions, as orders can be added, modified, or revoked through periodic reviews. A licensed customs broker can assist with scope rulings if the product's specifications are near the order's definitional boundaries.