Audemars Piguet Royal Oak Ref. 5402BA – an early, all‑yellow‑gold interpretation of Gérald Genta’s groundbreaking design. Introduced in 1977, just five years after the inaugural steel 5402ST, this reference remained in production until 1990 with fewer than 740 examples leaving Le Brassus. The 18 K yellow‑gold case and integrated bracelet showcase the iconic ‘Petite Tapisserie’ dial in slate‑grey, punctuated by slender baton hour markers and matching hands. A gilt‑framed date window with black numerals sits neatly at 3 o’clock, preserving the Royal Oak’s famously balanced aesthetic. Powering the watch is Audemars Piguet’s ultra‑thin automatic calibre 2121 – 36 jewels, a suspended rotor, and approximately 40 hours of power reserve – ensuring technical refinement equal to its timeless design.