HTS code 9902.11.88 covers "Expanded poly(tetrafluoroethylene) (PTFE) nonadhesive cellular sheets, of a thickness greater than 1.5 mm but not more than 3.0 mm, certified by the importer as having a tensile strength of at least 48.3 MPa (7,000 psi) per ASTM F-152 (CAS No. 9002-84-0) (provided for in subheading 3921.19.00)" 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.