An incredibly rare watch with just 50 pieces made specifically for the Hong Kong market, the Royal Oak Perpetual Calendar ref. 26606ST is one of Audemars Piguet's most visually distinctive and mechanically impressive models. While housed within a stunning white gold construction with the same bracelet and case design that we all know and love, the ref. 26606ST also features a beautiful green dial with AP's Petite Tappiserie pattern and a matching green alligator strap. Powered by the automatic cal. 5134 movement, this 41mm timepiece also packs a heavy horological fistful of complications with its perpetual calendar containing a date, day, week, month, leap year and moon phase indicator - which happens to add another tremendous splash of colour by virtue of its blue semi-circular aperture.