Black Bay ChronoThe Black Bay Chrono model seamlessly fuses TUDORs long history of crafting professional divers watches with a sports chronograph. This watch features contrasting sub counters and a high performance automatic Manufacture Caliber, with column wheel construction and vertical clutch. Boasting a 70 hour power reserve and a silicon balance spring, the Manufacture MT5813 Chronograph Caliber is certified by the Official Swiss Chronometer Testing Institute