Audemars Piguet · Royal Oak

Strap for Royal Oak Perpetual Calendar Openworked 41 Ceramic

Integrated bracelet: measurements, the most common questions, and the way to a made-to-measure strap.

Integrated bracelet

The Audemars Piguet Royal Oak 26585CE.OO.1225CE.01 is designed with a bracelet integrated into the case. For a compatible made-to-measure strap, the Casati Milano atelier builds it on your watch.

Case diameter41 mm
Reference26585CE.OO.1225CE.01
FamilyRoyal Oak
MovementAudemars Piguet caliber AP 5135 hours, minutes | date, day, leap year, month, week indicator | moonphase
Year2019
CaseTitanium, Ceramic

Spring bar

Swiss Standard universal spring bars

The right category for this model · 316L steel, all lug widths 13–26 mm

The Royal Oak 26585CE.OO.1225CE.01, seen from the bench

The Royal Oak perpetual reference 26585CE.OO.1225CE.01 is powered by the automatic AP 5135 caliber with perpetual calendar and moon phase functions. The movement indicates hours, minutes, date, day, month, leap year and week indicator, as well as moon phases. The case features the characteristic octagonal design of the Royal Oak with an integrated visible bezel.

Frequently asked questions

Can a standard strap be fitted to the Royal Oak 26585CE.OO.1225CE.01?

No. The bracelet is integrated into the case — it is part of Genta's original design and does not include a standard lug. An off-the-shelf strap simply will not attach. The only option is a bespoke strap built directly around the watch.

How does the bespoke strap process work for this Royal Oak?

I make it at <a href="/pages/casati-booking">Casati Milano</a>, by appointment only, at Via XX Settembre 15 in Milan. I bring the watch to the bench, take measurements from the actual titanium and ceramic case, and build the attachment around the real dimensions. There are no shortcuts — every millimetre has to be verified by hand.

Which leather do you recommend for this model?

I prefer Mississippi alligator with a matte finish. The Royal Oak has a sporting character built on precise geometry — matte alligator respects that tension without overwhelming it. I avoid glossy leathers: against titanium and ceramic, they clash.

How long does a well-made strap last?

A properly crafted alligator strap holds up for five, even eight years of daily wear. The leather ages — it shifts in tone, takes on the creases of the wrist — and that is entirely natural; it is what makes it singular over time. Keep it away from prolonged moisture and let it breathe between wears.

Do the eight hexagonal screws on the Royal Oak serve a technical purpose, or are they purely decorative?

They started out functional: they were meant to seal the bezel on a case designed in 1972 to withstand water pressure. Genta left them visible because he liked the look — and from that moment they became the defining mark of the entire Royal Oak family. They are real screws, not engraved decoration.

The next step

The right strap isn't chosen. It is built, together.

From the atelier appointment to delivery, every step is made for those who know that things done well take time. Rare leathers, one piece at a time, eighteen months of warranty.

Request an appointment →

Casati Milano · Via XX Settembre 15, Milan · by appointment only