Though the Audemars Piguet Royal Oak Offshore line is usually about sporty aesthetics, there are exceptions, like the Royal Oak Offshore Tourbillon Chronograph Carbon. Oversized and chunky with a carbon composite case, it looks like the typical Offshore but the movement is special. The calibre 2897 is an automatic chronograph with tourbillon, wound by a peripheral rotor. This movement is not new, but for the first time the winding mechanism has been revealed on the dial.

With a three armed cage and a twin-colour balance wheel, the tourbillon is in the signature style of Renaud & Papi

A cut-out at one o’clock shows the winding gear and the ball bearing for the rotor. And the chapter ring of the dial with the minute markings is actually clear sapphire, revealing the peripheral rotor with its teeth that run all around the edge of the dial.

A typical winding rotor is a semicircular weight that covers half the movement. Here the movement can be admired in its entirety since the oscillating weight is just a slim piece of platinum that sits on the perimeter of the movement.

Constructed in the style typical of Renaud & Papi, the respected movement specialist owned by Audemars Piguet, the movement combines both classical and modern watchmaking. The bridges and chronograph mechanism are reminiscent of old pocket watches, and so is the grande sonnerie style winding click on the barrel.

The case is 44 mm in diameter, and made of carbon composite (essentially strands of carbon fibre mixed with a polymer), while the bezel, pushers and crown are ceramic. And the crown guard and case back are titanium.

Notably, the ceramic is finished to a remarkable degree that only Audemars Piguet has achieved in watchmaking. Unlike most ceramic watches which have a easy to achieve mirror polished surface, the ceramic bezel for example has a brushed top and polished flanks, with a brilliantly sharp edge in between.

With a price tag of US$273,200, this will be made in a limited edition of just 50 watches.