Classification of combination articles follows the principal-function rule and the relevant Section notes. A clock radio is generally classified as a radio receiver under Chapter 85 if the radio function is considered principal, but if the article is designed primarily as a clock with a radio as an ancillary feature, Chapter 91 may apply. CBP has issued rulings on specific models; requesting a binding ruling is the most reliable approach for these combination goods.

Many clock lines under heading 9105 sourced from China are subject to Section 301 measures. The specific tariff line (10-digit HTS) and the country of origin determine whether a measure applies and at what list. Importers should verify the applicable list and any exclusions that may have been granted for the specific product, as the Section 301 landscape for this heading has evolved over successive rounds of action.