What is COSC?
COSC stands for Controle Officiel Suisse des Chronometres and is the Swiss Official Chronometer Testing Institute. A mechanical chronometer certified movement must be accurate to within -4 to +6 seconds per 24 hours. This amounts to a 99.99% rate of accuracy. The entire current Breitling line of watches, mechanical and quartz, is being submitted for certification. Are all Breitling watches COSC certified? Not all old Breitling models are COSC certified, but all watches manufactured in 2000 or later are. This is true for both mechanical movements and quartz movements. Is my watch COSC certified? If it was manufactured in 2000 or later, it definitely is. If it is older, an easy (but not guaranteed) way to find out is to look for the word “CHRONOMETRE” on the dial or case back. Also, you can check the model number on the case back. If the fourth character is a “3”, the watch is certified. If not, the character is a “0”. If it is a newer watch, a COSC certificate was also given to you at t
