Minerva 66
Minerva Calibre 66 is a hand winding chronograph calibre used by Montblanc.
A dual-balance/escapement system, Calibre 66.25 features 18,000 A/h timekeeping and 360,000 A/h chronograph. This allows the chrono to measure 1/100 second increments. But this fast movement limits power reserve to just 45 minutes for the chronograph function. Happily, the main timekeeping function will 100 hours between windings.