Introducing the Audemars Piguet Royal Oak Selfwinding Chronograph 26240ST.OO.1320ST.04. The 41mm case is made of stainless steel and complements the Grande Tapisserie dial in khaki green. Luminescent hand and hour markers work with the Sapphire glare-proofed crystal for optimal legibility in any condition. An exhibition case back gives a glimpse at the "50th Anniversary" oscillating weight. The calibre 4401 powers all of the watch's complications, including Flyback chronograph timekeeping and date features.