Audemars Piguet. A fine 18K gold automatic perpetual calendar wristwatch with moon phases

Audemars Piguet. A fine 18K gold automatic perpetual calendar wristwatch with moon phases
Signed Audemars Piguet, Automatic, Quantième Perpetuel Automatique, no. 535, ref. 5548, movement no. 225'553, case no. B 61543, manufactured in 1981
Cal. 2120/1 nickel-finished lever movement, 36 jewels, 21K gold rim to the rotor, white dial, applied gold baton numerals, three subsidiary dials for month, day and date, aperture for moon phases and lunar calendar, circular case, stepped bezel, snap on back, 18K gold Audemars Piguet buckle, case, dial and movement signed
36 mm. diam.