; and (B) by striking 12/31/2020 and inserting 12/31/2024 . (186) Mixtures of C5–C18 perfluorocarbon alkanes, perfluorocarbon amines, and perfluorocarbon ethers Heading 9902.10.57 is amended— (A) by amending the article description to read as follows: Mixtures of C5–C18 perfluorocarbon alkanes, perfluorocarbon amines, and/or perfluorocarbon ethers (CAS No. 86508–42–1) (provided for in subheading 3824.99.92) ; and (B) by striking 12/31/2020 and inserting 12/31/2024 . (187) Methoxysilanated amorphous poly alpha olefin Heading 9902.10.69 is amended— (A) by amending the article description to read as follows: Silane, ethenyltrimethoxy-, reaction products with 1-butene-ethylene-propene polymer (CAS No. 832150–35–3) (provided for in subheading 3902.30.00) ; and (B) by striking 12/31/2020 and inserting 12/31/2024 . (188) Acid form dispersion Heading 9902.10.79 is amended— (A) by amending the article description to read as follows: Poly(1,1,2,2-tetrafluoro-2-[(trifluoroethenyl)oxy]ethanesulfonyl fluoride-co-tetrafluoroethylene) (CAS No. 1163733–25–2) (provided for in subheading 3904.69.50) ; and (B) by striking 12/31/2020 and inserting 12/31/2024 . (189) Fluoropolymer lithium salt powder Heading 9902.10.81 is amended— (A) by amending the article description to read as follows: Poly(1,1,2,2-tetrafluoro-2-[(trifluoroethenyl)oxy]ethanesulfonyl fluoride-co-tetrafluoroethylene) lithium salt (CAS No. 1687740–67–5) (provided for in subheading 3904.69.50) ; and (B) by striking 12/31/2020 and inserting 12/31/2024 . (190) Fluoropolymer, polyvinyl, ammonium salt Heading 9902.10.82 is amended— (A) by amending the article description to read as follows: Poly(1,1,2,2-tetrafluoro-2-[(trifluoroethenyl)oxy]ethanesulfonyl fluoride-co-tetrafluoroethylene) ammonium salt (CAS No. 1126091–34–6) (provided for in subheading 3904.69.50)