Also known as “C.O.S.C.”. Abbreviation for “Contrôle officiel suisse des chronomètres”, French for “Swiss chronometer testing bureau.” COSC is a Swiss-government-sponsored agency that tests watches submitted to it and issues chronometer certificates to those that are precise enough to meet COSC standards. COSC operates three testing facilities: in Bienne, Le Locle and Geneva.
All items in C:
- CENTER, OR SWEEP SECONDS HAND
- CHAPTER RING
- COLUMN WHEEL
- COSC (OR C.O.S.C.)