BRAND : Audemars Piguet MODEL : Royal Oak Selfwinding Chronograph MODEL NUMBER : 26331BA.OO.1220BA.01 CASE : 18-carat yellow gold case, glareproofed sapphire crystal, screw-locked crown. CASE SIZE : 41 mm WATER RESISTANCE : 50 m DIAL : Blue dial with “Grande Tapisserie” pattern, yellow gold-toned counters, yellow gold applied hour-markers and Royal Oak hands with luminescent coating. CALIBRE : SELFWINDING CALIBRE 2385 MECHANISM : Selfwinding POWER RESERVE : 40 hours FUNCTIONS : Chronograph, hours, minutes, small seconds and date.