HTS code 9818.00.03.00 covers "Spare repair parts or materials (other than nets or nettings) which the owner or master of a vessel certifies are intended for use aboard a cargo vessel, for installation or use on such vessel, as needed, in the United States, at sea, or in a foreign country, but only if duty is or has been paid under this schedule upon first entry into the United States of each such spare part or material purchased in, or imported from, a foreign country" 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.