HTS (Harmonized Tariff Schedule) Codes are 8-10 digit product classification codes that are used to determine customs duties you will need to pay upon importing to the U.S. The first six digits, known separately as the HS code, are universal. Subsequent digits are then assigned to provide further classification specific to the country of import. U.S. HTS codes are 10 digits and are administered by the U.S. International Trade Commission.
Your supplier may be able to provide you with an HTS code, but do note that many Chinese suppliers will supply the Chinese variation of the HTS code. Since the first six digits of an HTS code consists of a universal HS code, you need to determine the final four digits of the HTS code for U.S. import using the Harmonized Tariff Schedule.