Audemars Piguet Royal Oak Perpetual Calendar 25820SP, 2000s Stainless steel octagonal case, n.F77713-N°0343, octagonal platinum bezel. Black dial with tapisserie finishing, counters with argenté outer track, applied indexes, indication of the date, day of the week, month, leap year, phases and age of the moon. Automatic movement, cal. 2120, n.549884. Stainless steel and platinum Audemars Piguet integrated bracelet. Size: 39 mm.  Accompanied by Audemars Piguet warranty , instructions booklet and winding box. Notes: Launched in 1996 and in production until 2013, reference 25820 introduced the leap year indication in the Royal Oak perpetual calendar collection. The model was made in a total of 1235 pieces, and among these only 378 in stainless steel and platinum like the present watch.