Audemars Piguet Royal Oak Perpetual Calendar 26579CB.OO.1225CB.01
Extra-thin movement with suspended barrel. The oscillating weight is guided by a peripheral ring rolling on four ruby runners, which reduces friction and wear to the minimum possible. The moon phase indicator is laser microstructured and laid on an aventurine base. The moon phase astronomical indicator requires a correction every 125 years and 317 days. The movement is based on the earlier 2120.