8409.91.10.60 - For marine propulsion engines

This HTS classification, 8409.91.10.60, specifically covers parts designed for marine propulsion engines. These are components intended for use solely or principally with the internal combustion engines falling under headings 8407 or 8408, where the ultimate application is to power a vessel or watercraft. The description "For marine propulsion engines" emphasizes the critical end-use requirement for classification within this specific sub-heading.

This category is distinguished from its sibling, 8409.91.10.40, which pertains to engine parts for various land vehicles (trucks, buses, passenger cars, etc.) as identified by their respective subheading or heading references. While both relate to engine parts, the defining characteristic here is the marine application, setting it apart from terrestrial vehicular use. It also differs from the broader "Other" category (8409.91.10.80) by being more precisely defined for marine propulsion.

As this is a leaf node within the HTS structure, there are no further subcategories branching from 8409.91.10.60. Therefore, the focus for classification remains on ensuring the part's intended use is exclusively for marine propulsion engines that are either spark-ignition or compression-ignition internal combustion piston engines. Classification hinges on this direct relationship to marine power generation, distinguishing it from general engine components or those destined for other modes of transport.