A case clad with precious metal involves a mechanical or metallurgical bonding of a precious-metal layer to a base-metal substrate, resulting in a durable composite. Electroplating or thin surface coatings generally do not meet the 'clad' standard and would place the watch under heading 9102 (base-metal case). The thickness and bonding method of the precious-metal layer are the key technical facts to document.

A smartwatch whose principal function is data processing or communication may be classified outside Chapter 91 entirely, typically in Chapter 85, regardless of case material. Chapter 91 note provisions exclude articles that are classifiable in Chapter 85 as electronic devices. If the article is principally a timepiece with smart features, 9101 may apply, but a binding ruling is advisable given the functional complexity.