The 15500ST is the 41 mm steel Royal Oak Selfwinding with date that Audemars Piguet introduced in 2019 as the successor to the 15400ST. The main lines of Gérald Genta's design remained: the octagonal bezel with eight hexagonal screws, the integrated bracelet with tapering links and the Grande Tapisserie dial. The details changed, including broader indices and hands.
Inside is the in-house calibre 4302, a larger movement than the predecessor's 3120, with a frequency of 4 Hz and a power reserve of about 70 hours. The 22 ct gold rotor is visible through the display back. The watch is water-resistant to 50 metres.
The 15510ST followed as early as 2022, giving the 15500ST a relatively short production run. On a pre-owned example we look above all at the alternation of brushed and polished surfaces, because polishing marks on case and bracelet are easy to see on a Royal Oak, at the folding clasp and at the completeness of the set, with certificate and guarantee card.