Launched in 1972 at Basel Fair, Audemars Piguet's introduction of the Royal Oak marked the beginning of the luxury sports watch market we know today, causing an immediate sensation as the watch industry had never seen anything comparable before. At the time the most expensive steel wristwatch available, it most notably housed the extra slim caliber 2121 based on the Jaeger-LeCoultre cal. 920, that would later be found in the Nautilus wristwatch. Today, the Royal Oak remains as iconic as ever, with early examples being exceedingly popular and collectible.

The Royal Oak model reference 5402 has been produced in four different batches: A, B, C and D with small design details that made each subtly different. Presented in excellent condition, the present "B series" Royal Oak is a rare and extremely sought after Audemars Piguet. It is thought that from the original "A-series" production, 2000 pieces were manufactured, while the total production of "B-series" was just 1000 examples.The dial is preserved in excellent condition with the AP logo at 6 o'clock as correctly found on any A and B Series as well as some C Series, furthermore upon closer inspection one can also notice that the clasp is stamped Audemars Piguet.