A final flourish for Calibre 5135: the 150th Anniversary Royal Oak Perpetual Calendar

In the 150th Anniversary Royal Oak Perpetual Calendar, Audemars Piguet turns a farewell into an exhibition of finishing. The historic openworked automatic Calibre 5135 is on view beneath a distinctive blue chapter ring and subsidiary calendar displays. Vintage-inspired lettering, calendar scales and the realistic moonphase introduce warmth and contrast to the unmistakably industrial Royal Oak.

The 41mm case and integrated bracelet combine lightweight titanium with Bulk Metallic Glass, a palladium-rich amorphous alloy noted for its luminous surface and resistance to wear. That material contrast continues the Royal Oak tradition of making case construction central to the design, rather than simply housing the mechanics.

Released in February 2025 in a series of 150 pieces, the watch marks the final appearance of Calibre 5135. Its 40-hour reserve and 2.75Hz frequency belong to an established movement lineage. The special edition captures the tension between enduring engineering and a calendar display that never stops inviting closer inspection.