Tudor Care
METAS Certification

The TUDOR Black Bay Ceramic, the Black Bay and the new Black Bay 58 GMT have undergone a series of rigorous tests in order to achieve the status of Master Chronometer, awarded by METAS.


METAS Master Chronometer certification is comprehensive and covers the main functional characteristics of a watch including precision, resistance to magnetic fields, waterproofness and power reserve. Its standards are incredibly high, starting with precision. In order to qualify, a watch must be able to function within a 5-second range of variation each day (0 +5), that is to say 5 seconds less than the Official Swiss Chronometer Testing Institute (COSC) (-4 +6) carried out on a single movement and a second less than TUDOR's internal standard, which is applied to the brand's models with a Manufacture Calibre (-2 +4).

Metas certification

The certification also guarantees the timekeeping accuracy of a watch subjected to magnetic fields of 15,000 gauss. Finally, it also guarantees that the waterproof capability claimed by the manufacturer conforms with the International Organization for Standardization (ISO), as does the power reserve of each Master Chronometer watch. It should also be noted that two prerequisites are necessary before the certification can be obtained: manufacturing must conform with the criteria of Swiss Made, and the movement must be certified by the Official Swiss Chronometer Testing Institute (COSC).


All the tests and prerequisites leading to Master Chronometer certification, which the Black Bay Ceramic, Black Bay, and the Black Bay 58 GMT have achieved, are summarised below:

- Swiss Made

- Certification by the Official Swiss Chronometer Testing Institute (COSC)

- Precision at two temperatures, in six different positions and at two different levels of power reserve: 100% and 33%

- Smooth functioning when exposed to a magnetic field of 15,000 gauss and precision following exposure

- Waterproof to 200 m (660 ft)

- 65-hour or 70-hour power reserve