The Royal Oak 15451 made its first appearance in 2012. Its case measures 37mm across and features a bezel set with 40 brilliant-cut diamonds. Like its non-diamond cousin 15450, it is powered by the self-winding caliber 3120. Reference 15451ST.ZZ.1256ST.03 has a steel case and matching bracelet. The dial is blue. It was added to the collection in 2017.
The in-house caliber 3120 has a total of 280 parts. The rotor, in 22ct gold, is mounted on ceramic ball bearings.