TL;DR: The Royal Oak Double Balance Wheel Openworked (ref. 15407ST.OO.1220ST.01) takes AP's skeletonized design tradition and builds it around a genuinely rare mechanism: two balance wheels and hairsprings mounted on the same axis for added stability. Introduced in 2016, it's a 41mm steel case running the in-house Caliber 3132. Here's why this reference stands apart even within AP's own Royal Oak lineup.
Most skeletonized watches show off finishing. This one shows off an actual mechanical innovation most brands never attempt.
Where does this reference actually fit in AP's history?
Introduced in 2016, the Double Balance Wheel Openworked builds directly on the original Royal Oak, designed by Gérald Genta in 1972. AP's openworked, skeletonized aesthetic goes back to the 1930s, and this model pushes that tradition further by integrating a genuinely dual balance wheel system, adding genuine precision benefits on top of the usual visual appeal of a skeletonized dial.
What actually makes the double balance wheel mechanism significant?
The self-winding Caliber 3132 runs two balance wheels and two hairsprings mounted on the same axis, oscillating together to improve stability and precision, a genuinely uncommon mechanical approach even at this tier. It operates at 21,600 vibrations per hour with roughly 45 hours of power reserve. The skeletonized construction gives an unobstructed view of the mechanism, and the finishing has to hold up to that scrutiny since there's nowhere for the movement to hide.
What does the case and dial actually look like?
A 41mm stainless steel case with the Royal Oak's signature octagonal bezel and eight hexagonal screws. The slate grey openworked dial pairs pink gold applied hour markers with luminescent Royal Oak hands, keeping the piece genuinely legible despite the skeletonized complexity underneath. The integrated steel bracelet and AP folding clasp deliver the same comfortable, seamless fit the Royal Oak is known for everywhere else in the line.
How does this reference actually compare to other Royal Oak models?
Against the Royal Oak "Jumbo" Extra-Thin, which leans entirely into sleekness and minimalism, this reference goes the opposite direction, intricate and mechanically dynamic rather than restrained. Compared to something like the Patek Philippe Nautilus, which stays understated by design, the Double Balance Wheel Openworked puts its mechanical artistry on full display rather than hiding it, appealing directly to a collector who wants the engineering fully visible rather than just implied.
Is this reference actually worth building a collection around?
For a collector chasing genuine technical mastery alongside AP's iconic silhouette, yes. The combination of an uncommon mechanical approach, instantly recognizable Royal Oak design language, and AP's manufacturing depth makes this a genuinely distinctive addition to any serious collection.
What should you check before buying one pre-owned?
Confirm the specific reference and production year, since skeletonized AP references carry meaningful finishing variation worth inspecting closely. Check box, papers, and service history the same way you would with any serious AP purchase, and understand that servicing a double balance wheel movement properly requires a specialist genuinely familiar with the mechanism.
If this reference has caught your eye, reach out and we'll walk you through what's actually available.
Jerred at KROLUX
