HTS code 9903.45.30 covers "Quartz surface products, as defined in U.S. note 41(a) to this subchapter, when the product of any country not exempt under U.S. note 41(c) to this subchapter, if entered in an aggregate quantity not exceeding the quantity defined in U.S. note 41(d) to this subchapter" under the US Harmonized Tariff Schedule. This is the official duty rate charged by US Customs when this product is imported into the United States, sourced directly from the U.S. International Trade Commission and refreshed daily.