Audemars Piguet Royal Oak Tourbillon Extra-Thin Openworked Steel — Skeleton Dial | Ref. 26518ST.OO.1220ST.01

Among the most technically demanding achievements in contemporary watchmaking, the Royal Oak Tourbillon Extra-Thin Openworked transforms Genta's architectural masterpiece into a transparent landscape of haute horlogerie mechanics. Reference 26518ST presents the iconic 41 mm octagonal form in stainless steel — a democratically luxurious material choice that lets the movement speak without precious metal distraction — with the dial and movement skeletonised to expose every bridge, wheel, spring and tourbillon cage in meticulous relief. The result is a watch that functions simultaneously as a timekeeping instrument and a kinetic sculpture.

Driven by a hand-wound movement — a deliberate choice that embodies the extra-thin philosophy, eliminating the thickness of an automatic rotor — the calibre is developed, decorated and assembled entirely within AP's Le Brassus manufacture. The flying tourbillon cage completes one rotation per minute, visible in full through the open-worked architecture of the dial, while rhodium-toned bridges and bevelled edges are finished by hand to the standards of the finest Swiss fine watchmaking tradition. The stainless steel bracelet with its integrated design mirrors the case's technical severity, creating a cohesive, monochromatic aesthetic.

Produced between 2017 and 2022, the 26518ST represents the most accessible entry point into the Royal Oak Tourbillon Extra-Thin family — yet accessible is a relative term for a piece of this horological distinction. Steel tourbillons from AP are fiercely contested on the secondary market, consistently outperforming more overtly precious variants in collector desirability surveys. For the discerning enthusiast, this is the definition of a grail acquisition. Presented with box and papers.