The Audemars Piguet Royal Oak Perpetual Calendar reference 26574BA.OO.1220BA.01 was introduced in 2016, according to AP marking a grand return of yellow gold. At 41mm, its case is slightly larger than its predecessors. Accordingly, the self-winding caliber 5134 is slightly larger as well – plus a week number indicator has been added. In this configuration, case and bracelet are yellow gold; the dial is blue.
