Cal.2120-2, rhodium plated 38 jewel movement adjusted to heat, cold, isochronism and five positions with self-compensating flat hairspring and 21k gold lined rotor, white dial with applied gold baton markers, gold baton hands, subsidiary dials for day, date and month indicators, aperture for lunar phases, three-piece circular case with stepped bezel, calendar adjusters to the band, on black strap with 18k gold Audemars Piguet double folding buckle, case, dial and movement signed diameter 36mm.