HTS code 9902.15.47 covers "Pistons suitable for use solely or principally with marine propulsion engines, such pistons each having a cast steel crown and aluminum body, weighing 12 kg or more (provided for in subheading 8409.99.92)" 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.