The 26331ST is the 41 mm steel Royal Oak Chronograph that succeeded the 26320ST in 2017. Its hallmark is the dial with a Grande Tapisserie pattern and three sub-dials, in versions where the sub-dials are often in a contrasting colour, giving the watch a sportier look than the Royal Oak Selfwinding.
Calibre 2385 is a self-winding chronograph movement based on a Frédéric Piguet movement, adapted and finished by Audemars Piguet, with about 40 hours of power reserve and visible through the display back. The watch has a date and is water-resistant to 50 metres. Its successor is the 26240ST with the integrated in-house calibre 4401.
On a pre-owned example we test the chronograph completely: start, stop, reset and the running of the sub-dials. We also look at the pushers and crown, at the finishing of case and bracelet, and at the set. Because a chronograph has more parts than a simple movement, the date of the last service is particularly relevant here, and we state it when it is known.