Defined by its signature octagonal silhouette, the Royal Oak 15400ST.OO.1220ST.03 is housed in a 41mm stainless steel case featuring a fixed bezel secured by eight hexagonal screws and a screw-locked crown. A glareproofed, scratch-resistant sapphire crystal protects the dial, while a glareproofed sapphire exhibition case back reveals the movement within.
The blue dial draws immediate attention, set with white gold applied hour markers finished with a luminescent coating for reliable low-light legibility. Hours, minutes, central seconds, and date are all accounted for, presented across the dial in a clean, well-organized layout. The stainless steel bracelet is fastened by an AP folding clasp and the watch carries a water resistance rating of 50 meters (165 feet).
Driving the watch is the self-winding AP Calibre 3120, an automatic movement delivering a power reserve of approximately 60 hours. This example is pre-owned in excellent condition and is offered as a complete set, including the original Audemars Piguet box, warranty papers dated 2015, and the official AP tag.
