Laboratoire Dubois SA is an independent Swiss test laboratory in Le Locle, founded by Pierre Dubois in 1947, that specialises in mechanical, environmental, and material testing of watches and watch components. Through the 1960s and 70s the lab grew as the standard third-party test house for the Swiss watch industry, performing water-resistance pressure tests, shock testing, magnetic susceptibility, and material analysis on a contract basis. The lab's current address (Avenue du Technicum, Le Locle) is shared with the equally venerable Dubois Dépraz movement-module specialist next door, but the two firms are separate businesses with shared roots in the same family.
The Chronofiable test was developed by Laboratoire Dubois in the 1980s as a comprehensive ageing-and-stress protocol that addressed an industry gap: COSC certified the bare movement on a bench, and water-resistance tests certified static pressure tolerance, but no standardised test certified that the complete watch would survive sustained real-world wear. The Chronofiable protocol bundles multiple stress sub-tests into a single 21-day cycle on the cased watch, with timekeeping checked at start and end.
"Chronofiable is what tells you a watch has been engineered for the wrist, not just the bench. The bench tells you it works new. Chronofiable tells you it will still work in six months."- Watchmaker on Tudor Manufacture calibre programme
The protocol consists of (typically): (1) magnetic exposure cycles; (2) temperature swings between -10°C and +50°C; (3) humidity / dust ingress; (4) at least several thousand crown rotations simulating winding and time-setting wear; (5) several thousand chronograph push-button cycles where applicable; (6) mechanical shocks at multiple intensities; (7) linear and rotational accelerations simulating wrist movement during normal wear. The watch must remain inside its declared rate specification at the end of the 21 days; failures are returned to the brand for analysis.
Tudor adopted the Chronofiable test as a per-batch certification for its Manufacture calibre family (MT5602, MT5612, MT5813, MT5402, etc.), introduced from 2015 onward. Every Tudor watch with an MT-series movement carries the in-house "Manufacture Calibre" mark, which combines COSC chronometer certification with Chronofiable per-batch validation. Breitling uses the test for selected pilot references; Bell & Ross and Sinn use it (or close equivalents from their own facilities) for military-spec references; multiple smaller independents subscribe on a contract basis.
The Chronofiable test is not a per-watch certification. Unlike METAS Master Chronometer (which certifies every individual watch by serial number), Chronofiable is a per-batch / per-design test: a representative production sample is subjected to the protocol; if it passes, the entire batch carries the certification. This is closer to automotive crash-testing than to per-unit metrology. The trade-off is volume and cost: every Tudor coming off the line has gone through COSC individually, but the Chronofiable certification is a population-level statistical guarantee rather than a per-watch test.
The Chronofiable test is complementary, not a competitor, to COSC and METAS. A Tudor Black Bay 58 with an MT5402 movement is both COSC-certified and Chronofiable-validated. The Pelagos FXD METAS (2024) stacks all three: COSC base, METAS Master Chronometer (per-watch, anti-magnetism), and Chronofiable (per-batch, wear simulation). Together the three certifications represent the most complete consumer-watch quality programme in Swiss watchmaking, and Tudor markets the combination as the modern industry benchmark.