Heading 9107 covers switches whose timing function is driven by a clock or watch movement or a synchronous motor — the timekeeping mechanism is integral to the article's identity. A timing relay in Chapter 85 typically uses electronic or electromechanical delay circuits rather than a horological movement. When the timing element is a microcontroller or RC circuit rather than a mechanical or synchronous-motor escapement, Chapter 85 is generally the correct destination.

The value breakpoint is applied to the customs value as appraised by CBP — generally transaction value under 19 U.S.C. § 1401a — not the list or invoice price alone. Importers should ensure their valuation methodology is consistent with CBP appraisement rules, particularly when related-party transactions or assists are involved.