Chronometer

A watch that has obtained a certificate from an official neutral testing center such as “COSC” (Controle Officiel Swiss des Chronometres) or “SOCC” (Swiss office for chronometric controls) after having passed strict precision tests for accuracy. These tests are performed in a laboratory over a minimum 15-day period. They test the movement alone, using successive daily rate figures at different temperatures and with the movement in different positions.