Audemars Piguet Royal Oak Ref 5402BA an early, all yellow  gold interpretation of Gerald Gentas 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 18k 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 Oaks famously balanced aesthetic. Powering the watch is Audemars Piguets 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.