Section XVI · Nuclear reactors, boilers, machinery and mechanical appliances; parts
8421.31
Intake air filters for internal combustion engines
Chapter
Nuclear reactors, boilers, machinery and mechanical appliances; parts
Heading
The product family within the chapter
Subheading
The specific good, identical worldwide
The first six digits are the same in every country that uses the Harmonized System. The United States adds two more for the tariff rate and, often, two more for statistics — which is why the rates below are listed against 8- and 10-digit numbers rather than against this code.
How the schedule reaches this code
- 84Nuclear reactors, boilers, machinery and mechanical appliances; parts
- 8421Centrifuges, including centrifugal dryers; filtering or purifying machinery and apparatus, for liquids or gases; parts thereof:
- Filtering or purifying machinery and apparatus for gases:
- Intake air filters for internal combustion engines
Published US duty rates
Duty is set at the 8- or 10-digit line, not at this 6-digit subheading, so more than one rate can sit under this code.
- 8421.31.00.00Intake air filters for internal combustion enginesNo.
- General
- 2.5%
- Special (FTA)
- Free (A,AU,B,BH,C,CL,CO,D,E,IL,JO,KR,MA,OM,P,PA,PE,S,SG)
- Column 2
- 35%
Only if the goods qualify under one of these programs.
Countries without normal trade relations.
Schedule footnotes
- See 9903.88.03.
A reference to Chapter 99 means an additional action — a Section 232 or 301 measure, an exclusion, or a quota — applies on top of the rate above.
This is the listed rate. Antidumping and countervailing duty orders, Chapter 99 actions and preference qualification all change what is actually collected, and classification is a judgement about your goods. Verify with your licensed customs broker before you file.
Other subheadings in heading 8421
- 8421.11Cream separators
- 8421.12Clothes-dryers
- 8421.19Other
- 8421.21For filtering or purifying water
- 8421.22For filtering or purifying beverages other than water
- 8421.23Oil or fuel filters for internal combustion engines
- 8421.29Other
- 8421.32Catalytic converters or particulate filters, whether or not combined, for purifying or filtering exhaust gases from internal combustion engines
- 8421.39Other
- 8421.91Of centrifuges, including centrifugal dryers:
- 8421.99Other
Source: U.S. International Trade Commission (USITC) — 2026 HTS Revision 12, released 2026-07-21, published at hts.usitc.gov. A U.S. Government work in the public domain.