The following proposed revocations of U.S. Customs and Border Protection classification rulings are included in the May 24, 2022, Customs Bulletin and Decisions. Comments on these proposed changes are due by June 24.

For more information on how to seek or utilize classification and other rulings, please contact attorney Deb Stern at (305) 894-1007 or via email. Click here to register for ST&R’s upcoming webinar on advanced classification topics.

Engine Parts

CBP is proposing to reclassify a timing chain tensioner and a tensioner arm assembly as parts of an engine under HTSUS 8409.91.50 (2.5 percent duty) rather than as parts of a motor vehicle under HTSUS 8708.99.8180 (2.5 percent duty). Rulings NY N246870 and NY N264869 would be revoked to reflect this change.

The tensioner consists of a steel housing, a spring, a rachet ring, and a plunger. In controlling the tension of the timing chain the tensioner performs a dampening function, maintaining the stability of the stretched chain during operation. The tensioner arm assembly comprises a plastic shoe and base that together attach to the timing chain and maintain its constant and regular orbit. One end is fixed to the engine with a bolt while the other transmits pressure from the tensioner to the chain and maintains its tension.

CBP explains that these items are integral, constituent parts of an engine because if the timing chain does not function properly power cannot be transferred to the camshafts in the precise ratio required. Similarly, without the precise functioning of the timing chain, the engine valves will not open and close properly and the engine will fail. Without the tensioner and the tensioner arm assembly, the timing chain cannot function and the engine cannot properly ignite the fuel mixture inside the cylinder.


CBP is proposing to reclassify a fluorescence confocal microscope as an instrument used in medical sciences under HTSUS 9018.19.40 (duty-free) rather than as an other microscope under HTSUS 9012.10.00 (duty-free). Ruling NY N300518 would be revoked to reflect this change.

The item at issue utilizes a confocal laser system with fiber optic probes that allow for the imaging of the internal microstructure of tissue. It consists of a wheeled platform that incorporates the requisite laser imaging system, a touchable user interface, connectors for the fiber optic probes, and other peripheral equipment, such as a thermic printer. It designed to enter the body for purposes of examining and obtaining endomicroscopic images and is suitable for use in a variety of applications, including gastroscopy, colonoscopy, bronchoscopy, and uteroscopy.

CBP explains that heading 9018 is more specific than heading 9012 because it covers a narrower set of items.

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