Audemars Piguet Royal Oak Men’s Watch 41MM Black Stainless Steel 15500ST. 50 m (5 ATM). The next evolution of the Ref. 15450 Self-winding Royal Oak comes in the 15500 form, which was introduced at the SIHH 2019. 03 has a stainless-steel case that is 41mm in diameter and 10.4mm thick with a glare-proof sapphire crystal and case back and a screw-locked crown. 03 has a black dial with a Grande Tapisserie pattern with updated white gold, wider luminous indexes and a date window that is further from the center of the dial. The most significant update to the Self-winding models is the in-house movement, which for the 15500ST. 03 is the self-winding caliber 4302 that has date functionality and a power reserve of 70 hours. The case is paired with a stainless-steel bracelet that has a fold over clasp. It has a water resistance of 50 meters (164 feet).