2019 Audemars Piguet Royal Oak Perpetual 26586ip

The 26586IP holds the record thanks to Caliber 5133, which is just 2.89mm thick, allowing the entire case to measure only 6.3mm in thickness. Unlike traditional perpetual calendars that require stacked components, this model re-engineers the layout into a single, ultra-flat layer, representing five years of R&D at Audemars Piguet’s Renaud & Papi division.

The titanium base ensures that the watch is exceptionally lightweight, enhancing wearability despite its complex mechanism. Meanwhile, the platinum 950 bezel adds a luxurious contrast and subtle brilliance. This bimetal construction also protects the watch from everyday scratches while maintaining its ultra-thin silhouette.

Despite the watch's slim profile, the dial is remarkably legible due to the blue satin-finished dial with white gold applied hour markers and luminous coating. The subdials are carefully proportioned for day, date, month, leap year, and moon phase, offering full calendar readability while maintaining a clean and minimalist aesthetic.

This watch is extremely limited, with only 200 pieces produced worldwide. It's considered a collector’s grail for its mechanical innovation and rarity. It was first revealed at SIHH 2018 as the RD#2 concept and later commercialized in this final form in 2021, maintaining its exclusivity through very limited availability.

The 26586IP blurs the lines between sports elegance and haute horology, showing that even the most complicated mechanical feats can be achieved in a wearable format. It sets a precedent for brands striving to combine everyday comfort with technical mastery, marking a milestone in the evolution of slim, complicated timepieces.