A Breguet ultra-thin in modern times
Founded in 1775 by Abraham-Louis Breguet (the inventor of the tourbillon, the gong-spring repeater, the perpetual calendar mechanism, and the ébauche-based Swiss watchmaking model still in use today), Breguet is one of the most historically significant watchmaking houses. The brand operates today within the Swatch Group as a haute-horlogerie manufacture in Le Sentier, Vallée de Joux. The Cal. 502.3 is the modern in-house ultra-thin automatic that powers most of the standard Classique catalogue: a 2.4 mm thin movement with all the Breguet finishing signatures.
Silicon hairspring pioneer
Breguet was one of the early industry adopters of silicon balance springs, alongside Ulysse Nardin and Patek. Breguet's silicon spring is manufactured in-house at the Le Sentier facility (within the broader Swatch Group ecosystem alongside ETA and Nivarox). The 502.3 ships with the silicon spring as standard, providing antimagnetic resistance and improved long-term rate stability. The spring is paired with a free-sprung balance with eccentric-poising weights for fine regulation without a regulator arm.
Breguet finishing identity
The 502.3 is finished to Breguet house standard:
- Hand-engine-turned 22k gold rotor with a guilloché pattern unique to Breguet
- Côtes de Genève on the bridges
- Polished bevels with hand-finished anglage
- Blued screws
- The Breguet "B" signature engraved on the rotor
The dial side carries equally distinctive Breguet vocabulary: blued Breguet pomme hands, frosted gold or silvered dials with guilloché patterns, painted Roman numerals, and the secret signature only visible at certain angles (the modern continuation of Breguet's 19th-century anti-counterfeit signature).
In the Classique 5197 and Marine 5517
The Cal. 502.3 powers the Classique 5197 (38 mm rose-gold or white-gold dress watch, the brand's entry to the Classique line), the Classique 7137 (with retrograde date and moonphase, more complicated dial), and the Marine 5517 (the modern interpretation of Breguet's historical naval chronometers, with a wave-pattern guilloché dial). The Marine 5517 in particular is Breguet's interpretation of a sport-dress hybrid, sitting somewhere between the elegant Classique line and the more athletic Type XX chronograph collection. Retail for the steel Marine 5517: approximately EUR 16,000; for the rose-gold Classique 5197: EUR 25,000+.
Where it sits
The 502.3 occupies a distinct position in modern watchmaking: a genuinely in-house silicon-equipped automatic from a brand with the most continuous heritage of any maker (Breguet has operated continuously since 1775 with brief interruptions). Comparable in-house ultra-thins include Piaget 430P (manual, 2.1 mm), JLC Cal. 849 (manual), Patek 240 (micro-rotor automatic), and the Bulgari BVL 138 Finissimo (record-thin automatic). The Cal. 502.3 sits in the upper-mid tier of this group: not the thinnest, but with the strongest historical association.