Royal Ammar bin Humaid Al Nuaimi spotted wearing a Audemars Piguet

Sheikh Ammar bin Humaid Al Nuaimi, Crown Prince of Ajman and one of the UAE's more watch-literate royals, was recently photographed wearing the Audemars Piguet Royal Oak Double Balance Wheel Openwork in stainless steel — reference 15407ST, from the brand's 2016 collection. The choice is telling: among the Royal Oak family's many complications, the 15407ST occupies a serious technical tier that goes well beyond aesthetic skeletonization.

At the heart of the 15407ST sits Calibre 3132, Audemars Piguet's self-winding movement featuring the brand's signature double balance wheel escapement. The dual oscillators — positioned at roughly the 10 and 4 o'clock positions on the movement — work in tandem to improve rate stability and reduce the effects of positional error. The movement operates at 3Hz and delivers a 60-hour power reserve. The 41mm stainless steel case maintains the Royal Oak's iconic octagonal bezel with eight hexagonal screws, tapisserie-patterned bridges, and an integrated bracelet — all hallmarks of Gérald Genta's 1972 masterwork, here given a thoroughly modern mechanical treatment.

From a collector standpoint, the 15407ST occupies a respected but accessible position within the Royal Oak ecosystem. It offers legitimate manufacture-level watchmaking — the double balance wheel is no marketing conceit — in the entry-adjacent steel configuration that has historically driven the most demand for the reference. The open-worked dial rewards extended wear: depending on light and angle, the movement architecture reads entirely differently, making it among the more visually dynamic daily-wear complications in AP's catalog.

Sheikh Ammar is no stranger to serious horology, and selecting the 15407ST over flashier tourbillon alternatives reflects a discerning preference for technical substance over statement jewelry. The stainless steel configuration, rather than the gold variants, further underscores that reading.

On the current market, the 15407ST trades at a modest premium over retail in steel, though nowhere near the multiples commanded by the Royal Oak Perpetual Calendar or Tourbillon references. With a UK list price of approximately £36,000, the grey market has remained relatively rational for this reference — making it one of the few genuinely complicated Royal Oaks still acquirable close to retail for patient buyers.