Audemars Piguet Royal Oak 4100BA, ‘80s 18k gold octagonal case and bezel, n.502. Grey dial with tapisserie finishing, luminescent applied indexes. Automatic movement, cal. 2123. 18k gold Audemars Piguet integrated bracelet, 18k white gold deployant buckle. Size: 35 mm.  Accompanied by Audemars Piguet instructions booklet and box. Notes: In production between 1977 and 1985, reference 4100 is the very first midsize version of the iconic Audemars Piguet Royal Oak.