Know that obtaining this certification is not easy task.
First, your watch has to be Swiss Made. It means having a Swiss movement with at least 50% of its pieces produced in Switzerland. Case up and final control also have to be made there. Finally, 60% of the added value, including the components, must be produced in Switzerland.
Now that your watch meets all the criteria, it has to obtain the COSC certification. The goal is to verify consistency and precision. For that, during the first 10 days of control, the watch has to have a -4sec/ +6sec range of variation per day. Obviously, it’s controlled while the watch is in 5 different positions and 3 different temperatures (3,23 and 38°C).
It’s important to note that only 6% of the annual Swiss production is COSC certified.
In addition to the Swiss Made and the COSC certification, METAS requires the brands whishing the certify their watches to create a control center inside their own factory.