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).
All the tests and prerequisites leading to Master Chronometer certification, which the Black Bay Ceramic and the new Black Bay 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)
- 70-hour power reserve