17
YOUR BREITLING CHRONOMETER
A chronometer is a high-precision instrument that has successfully passed the
entire battery of tests imposed by the COSC (Swiss Official Chronometer
t esting Institute), a neutral and independent body which individually tests
each movement according to the prescriptions in force.
t he certification test for wristwatches with sprung balance oscillators,
according to the ISO 3159 norm, consists of observing each movement for
15 days and 15 nights, in 5 positions and at 3 different temperatures (8°, 23°C,
38°C). In order to earn the prestigious chronometer label, a movement’s
performances must meet 7 very strict criteria, including a daily variation in
rate ranging between only –4/+6 seconds.
t he term “chronometer” should not be confused with that of “chronograph”,
which is a complicated watch fitted with an additional mechanism enabling
the measurement of the duration of an event. A chronograph is not neces-
sarily chronometer-certified, but all Br e It LIn g chronographs carry the much-
coveted title of “chronometers”.
To Next Page