9109.10.20 - Measuring not over 50 mm in width or diameter

This HTS category, 9109.10.20, specifically classifies complete and assembled electric clock movements designed for alarm clocks. The defining characteristic for inclusion here is the physical dimension of the movement, which must measure no more than 50 millimeters in either width or diameter. This precise measurement is a key distinguishing factor for customs purposes, ensuring accurate tariff application based on the physical size of the clockwork mechanism.

While this category falls under electrically operated movements for alarm clocks, it is further refined by its physical size limitation. Other categories at this level might cover movements for alarm clocks that exceed this 50 mm dimension or possess different operational characteristics or functionalities not explicitly defined by size. The focus on "not over 50 mm" serves to isolate smaller, often more compact, alarm clock movements.

As this is a leaf node within the HTS classification system, there are no further subcategories under 9109.10.20. Therefore, the classification is considered definitive once the criteria of being a complete, assembled, electrically operated alarm clock movement measuring 50 mm or less in width or diameter are met. This level of specificity is crucial for importers and exporters to ensure correct duty assessment and compliance with trade regulations.