Audemars Piguet Selfwinding Perpetual Calendar Ultra-Thin (RD#2)

Audemars Piguet's Royal Oak Selfwinding Perpetual Calendar Ultra-Thin (RD#2), reference 26586IP.OO.1240IP.01, measures 41 mm in titanium. The case is remarkably slim at 6.2 mm thick, a notable feat for a watch with this level of complication. A sapphire crystal covers the blue dial, which gives the perpetual calendar display a clean, legible backdrop. Inside runs the self-winding calibre 5133, which drives a perpetual calendar with date, weekday and month, along with a moon phase display. The combination allows the calendar to track leap years without manual correction until the next century. The bracelet is titanium, satin-brushed with polished platinum links, keeping the overall weight low on the wrist. Water resistance is rated to 50 metres, modest for a Royal Oak but consistent with its dress-watch proportions.