The Harmonized System (HS) Codes are designated codes used in international trade to help identify the type of commodities that are being shipped. You can find the full list of HTS codes here.
The Harmonized System (HS) is administrated by the World Customs Organization (WCO). It serves as the foundation for the import and export classification systems used in the United States and many other countries.
The first six digits of the HS codes are international and the last 4 digits are local digits that are added by the different countries for further classification.
In the U.S, the last 4 digits are known as a Schedule B number and there is a Schedule B number for every physical product possible. Schedule B is administered by the U.S. Census Bureau’s Foreign Trade Division, and they also offer a free online Schedule B search tool that comes in handy when trying to classify your products