9101.99 - Other:

This HTS category, 9101.99, encompasses "Other" watches where the case is made of precious metal or metal clad with precious metal, and which are not electrically operated. This serves as a residual category for such watches that do not fit into the more specific subheadings within the 9101.00 range, particularly those defined by their power source.

Distinguishing this category from its sibling, 9101.91, is crucial. While both fall under the umbrella of watches with precious metal or clad cases, 9101.91 specifically covers electrically operated versions. Therefore, 9101.99 applies to watches powered by mechanical movements (manual winding or automatic).

The subdivisions within 9101.99 are determined by the number of jewels present in the watch's movement. These jewels, typically synthetic rubies or sapphires, reduce friction and wear on critical moving parts, thereby enhancing accuracy and durability. The subcategories – "Having no jewels or not over 7 jewels in the movement," and "Having over 17 jewels in the movement" – along with the implied intermediate category for over 7 but not over 17 jewels, provide a basis for classifying these mechanical watches based on the precision engineering and complexity of their internal mechanisms.