HTS (Harmonized Tariff Schedule) codes are product classification codes between 8-10 digits. The first six digits are an HS code, and the countries of import assign the subsequent digits to provide additional classification. 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 note that many Chinese suppliers will supply the Chinese variation of the HTS code. Since the first six digits of an HTS code is 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. With an HTS code, you can estimate the customs duties you will need to pay upon importing into the U.S.