The HS structure gives priority to more specific headings. If an article is specifically described by heading 4014 (hygienic or pharmaceutical) or 4015 (apparel and gloves), it goes there rather than under 4016. Heading 4016 applies only when no other heading in Chapter 40 more precisely covers the article. The article's design intent, labeling, and the chapter notes all inform the determination; a CBP binding ruling is advisable for borderline goods.

Many tariff lines covering rubber gaskets, washers, and seals originating from China are subject to Section 301 measures. The applicable list and any product exclusions are maintained by the Office of the US Trade Representative and are updated periodically. Importers should verify the current status of the specific 10-digit HTS line and country of origin before filing entry.