Harmonized System

The Harmonized Commodity Description and Coding System (or Harmonized
System, HS) is a system for classifying goods in international trade,
developed under the auspices of the Customs Cooperation Council. Beginning
on January 1, 1989, the new HS numbers replaced previously adhered-to
schedules in over 50 countries, including the United States.

For the United States, the HS numbers and four additional digits are the
numbers that are entered on the actual export and import documents. Any
other commodity code classification number (SITC, end-use, etc.) are just
rearrangements and transformations of the original HS numbers.