Harmonized Tariff Schedule of the United States

"The HTS comprises a hierarchical structure for describing all goods in trade for duty, quota, and statistical purposes. This structure is based upon the international Harmonized Commodity Description and Coding System (HS), administered by the World Customs Organization in Brussels; the 4- and 6-digit HS product categories are subdivided into 8-digit unique U.S. rate lines and 10-digit non-legal statistical reporting categories."