8421.23.00.00 - Oil or fuel filters for internal combustion engines

HTS code 8421.23.00.00 specifically classifies oil or fuel filters designed for internal combustion engines. These filters are critical components in automotive, marine, and other industrial applications, serving the primary purpose of removing impurities from lubricating oils or fuels to protect engine components and ensure optimal performance. Their construction typically involves porous media, such as paper or synthetic fibers, housed within a casing that facilitates connection to the engine's fluid systems.

This category is distinct from its siblings, 8421.21.00.00 (water filters) and 8421.22.00.00 (beverage filters), by its specialized application. While all fall under filtering machinery for liquids, 8421.23.00.00 is exclusively intended for use with the oil or fuel circuits of internal combustion engines, whereas the others are for water purification or the filtration of potable liquids for consumption. The "Other" category (8421.29.00) would encompass liquid filters not specifically covered by the aforementioned subheadings.

As a leaf node within the HTS, 8421.23.00.00 does not have further subdivisions. Therefore, classification at this level relies on accurately identifying the filter's intended application for internal combustion engines. Examples include oil filters for cars, diesel fuel filters for trucks, and specialized filters for aircraft engines, all of which fall under this specific tariff item provided they are primarily designed for engine fluid purification.