Royal Oak Selfwinding 37mm (Diamond-Set, Grey)

AP introduced the 37mm Royal Oak as the ref. 15450 in 2012, pitched at the gap between the full-size men's watch and the smaller ladies' references. It was redesigned in 2022 alongside the rest of the Selfwinding range, becoming the 15550/15551 family (15551 denoting the diamond-set bezel) on a new calibre 5900 that shaved the case down from 9.8mm to 9mm.

This Audemars Piguet Royal Oak Selfwinding wears a 37mm stainless steel case, its bezel set with 40 diamonds, with a grey Grande Tapisserie dial. Calibre 5900 inside, on a stainless steel bracelet.

Fun fact: the calibre 5900 isn't an AP ébauche: it's built on a Vaucher Manufacture base, a detail AP doesn't lead with but that continues a habit older than the Royal Oak itself: AP has drawn on outside movement makers throughout its history.