Audemars Piguet Royal Oak Perpetual Calendar Openworked

About this reference

The Audemars Piguet Royal Oak Perpetual Calendar Openworked reference 25829TR was produced from the late 1990s through the mid-2010s. This reference is distinguished by its bi-metal construction, pairing a tantalum case and outer bracelet links with 18k pink gold bezels and center links. Collectors prioritize this model for its skeletonized caliber 2120/2802, an ultra-thin automatic movement visible through the sapphire dial and exhibition caseback. The use of tantalum, a dense and difficult-to-machine refractory metal, makes this variant significantly rarer than standard steel or gold iterations. Current secondary market valuations typically fall within the $250,000 to $400,000 range depending on condition and provenance. Production records suggest that fewer than 100 units of the 25829TR were manufactured, and a notable example sold at a Phillips auction in 2021 for approximately 302,000 CHF, confirming its status as a low-volume collector piece.