COSC

The COSC awards the title of "chronometer" to each watch deposited in its control offices and having successfully undergone 15 days of tests on the precision and stability of operation in 5 positions and at different temperatures. The COSC is a non-profit association of five Swiss cantons: Bern, Geneva, Neuchâtel, Solothurn and Vaud, with headquarters in La Chaux-de-Fonds.