After teasing the concept watch at SIHH 2018, Audemars Piguet has finally unveiled the production version of the Royal Oak Selfwinding Perpetual Calendar Ultra-Thin, the world’s thinnest automatic perpetual calendar wristwatch.

The titanium case has a 950 platinum bezel

The new timepiece (Ref. 26586IP.OO.1240IP.01) has a case profile of just 6.3 mm (as promised in the concept RD#2 watch last year) and it’s all down to the engineering of the incredible 2.89 mm thick automatic movement. However, unlike the RD#2 from 2018 which featured an all 950 platinum case and bracelet, the final production watch combines titanium and platinum for a significantly lighter feel.

The concept RD#2 unveiled at SIHH 2018

The main case is made from 41 mm wide satin-brushed titanium fitted with anti-glare sapphire crystal and a bezel in polished 950 platinum much like the Royal Oak Jumbo Extra-Thin 15202IP from last year. The case is fitted with a sapphire crystal caseback, a titanium screw-down crown and is water-resistant to 200 meters. It is paired with a satin-brushed titanium bracelet with polished 950 platinum links and titanium AP folding clasp.

The case of this self-winding perpetual calendar is just 6.3 mm thick

The dial is different from the concept watch too. The blue “Grande Tapisserie” pattern is replaced by a blue satin-finished dial. The dial has a slightly different arrangement to the regular perpetual calendar (such as Ref. 26574) thanks to a bigger dial, remember this is a 41 mm case. The moonphase is now placed closer to 12 o’ clock as a nod to the first perpetual calendar wristwatch produced by the brand in 1955.

Caliber 5133 is based on the Caliber 2121 used in the Royal Oak Extra Thin. The challenge on the 5133 was to reduce the number of stacks on the movement from three modules to one. The pursuit of engineering a single level movement from a three-storey one while keeping it efficient and robust was not an easy one. It took them five years of research and development to come up with the required solution. The movement has a 40-hour power reserve and beats at 2.75 Hz (19,800 vph).

Caliber 5133 has a power reserve of 40 hours

The perpetual calendar functions, normally arranged on three levels have been merged into one single layer. This was possible due to patented innovations: the end-of-the-month cam has been integrated to the date wheel, while the month cam has been combined to the month wheel. The geometry of each component has also been optimized from the onset, reducing adjustment and assembly time.

The Le Brassus brand has a long history of pioneering calendar watches and extra-thin mechanisms and this new timepiece is further proof of how the manufacture continues to evolve its techniques and savoire-faire. The watch is priced at CHF140,000 (without VAT).