Audemars Piguet. A fine, rare and elegant platinum openface perpetual calendar keyless lever dress watch with moon phases and box

Audemars Piguet. A fine, rare and elegant platinum openface perpetual calendar keyless lever dress watch with moon phases and box
Signed Audemars Piguet, no. 31'526, retailed by Allemann, Montreux, manufactured in 1924
Cal. 17 1/2 SVF nickel-finished lever movement, 19 jewels, bimetallic compensation balance, silvered dial, applied white gold Arabic numerals, outer dot minute divisions, white gold Cathedral hands, four sunk subsidiary dials for month and leap year, day, date and constant seconds with moon phases and lunar calendar, plain circular case, snap on back, case numbered, dial signed by retailer, movement signed by maker
46 mm. diam.