HTS code 9902.11.79 covers "Strips wholly of expanded poly(tetrafluoroethylene) (PTFE) (CAS No. 9002-84-0), noncellular, with adhesive backing, of a thickness greater than 3 mm but not over 30 mm, presented rolled in spools, certified by the importer as having a tensile strength of 24.1 MPa (3,500 psi) or higher per American Society for Testing and Materials (ASTM) F-152 (provided for in subheading 3916.90.50) " under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.