The Royal Oak self-winding watch is a unique timepiece from Audemars Piguet. This men's reference 15400ST features a distinct 41mm stainless steel case equipped with an anti-reflective sapphire crystal and a waterproof crown. Waterproof up to 50 meters, the case is properly equipped for any activity. A matching stainless steel bracelet with an AP folding clasp accompanies the dial, providing reliable all-day hold. A cross hatch or "Grande Tapisserie" black dial creates a sleek style and is set with white gold index hour markers and Royal Oak hands. The hands are coated with lume, providing a highly legible reading for easy timekeeping. The calibre 3120 self-winding movement is expertly crafted with 3,00 hz, bidirectional winding, and a 60-month power reserve for effortless timekeeping.