HTS code 2922.21.25.00 covers "Oxygen-function amino-compounds › Aminohydroxynaphthalenesulfonic acids and their salts › 1-Amino-8-hydroxy-4,6-naphthalenedisulfonic acid, monosodium salt" 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.