Navitimer B19 Chronograph 43 Perpetual Calendar

Breitling Navitimer B19 Chronograph 43 Perpetual Calendar Ref. PB1921251B1P1 . The highest expression of a Navitimer. A perpetual calendar caliber is a mechanical movement that knows how many days each month has, even on leap years. Knowing that February has 29 days on a leap year may just be one single day, but the mechanical complexity behind it is hard to overstate. The perpetual calendar Caliber B19 incorporates an additional set of components programmed to know exactly when that extra day happens within the four-year cycle. To make things more complicated the five calendar indications: day, date, month, moonphase, and leap year, all advance instantaneously from December 31 to January 1.