9902.15.46 - Cast-iron cylinder heads suitable for use solely or principally with marine compression-ignition engines, such parts with cylinder bore over 125 mm and weighing over 32 kg each (provided for in subheading 8409.99.92)

This HTS category, 9902.15.46, specifically designates cast-iron cylinder heads designed and intended for use with marine compression-ignition engines. The key defining characteristics for inclusion in this classification are that these cylinder heads must have a cylinder bore exceeding 125 millimeters and a weight greater than 32 kilograms each. These provisions are made under temporary legislation and modifications, referencing their base classification within subheading 8409.99.92.

Given the nature of Chapter 99, which is reserved for temporary legislative provisions, this category does not have direct product-focused siblings in the traditional sense like the HS Chapters 1-97. Instead, its "siblings" would be other temporary classifications within Chapter 99, each addressing unique temporary modifications or restrictions on various goods, rather than broad product categories. The critical distinction here is the specialized, high-specification nature of the cast-iron cylinder heads for marine engines, as opposed to general engine parts or other machinery not meeting these precise technical criteria.

As this is a leaf node, there are no further subcategories. The classification is definitive for the specified cast-iron cylinder heads that meet all the outlined technical and functional requirements. Importers must ensure that the goods precisely align with the description, including material (cast-iron), intended use (marine compression-ignition engines), cylinder bore size (over 125 mm), and individual weight (over 32 kg), to correctly apply this temporary tariff provision.