Audemars Piguet Royal Oak Perpetual Calendar Blue Dial 26574ST

Inside the case is a heavily modified Clone Calibre 5134 automatic movement developed to run the full calendar display. This is not a decorative arrangement of sub-dials or static hands. The movement is configured to drive the day, date, month, leap year, week, and moon phase indications through a working calendar module while maintaining automatic timekeeping.

The movement uses a bidirectional winding rotor and is rated for approximately 36 hours of power reserve. Decorative bridges are visible through the sapphire caseback, with finishing details intended to reflect the look of the original caliber style. For buyers focused on mechanical complexity, the main point here is straightforward: this reference is built around an operational calendar system rather than a simplified visual imitation.