The Royal Oak 15500-series was introduced in 2019. Compared to the earlier 15400 it features a new movement - the self-winding caliber AP 4302 rather than the 3120. The case measures 41mm across. It is available in a number of configurations: reference 15500ST.OO.1220ST.02 has a stainless steel case, matching bracelet and a grey dial.
SElf-winding movement with a power reserve of 70 hours.