HTS code 9902.13.82 covers "Nonwoven radial segment and chordal orientation brake segments of oxidized polyacrylonitrile fibers, made up and presented as cut otherwise than into squares or rectangles, such segments formed by needling web and unidirectional tow fabrics together, the foregoing designed for use in aircraft braking systems (provided for in subheading 6307.90.98)" 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.