Cartier Rotonde de Cartier Perpetual Calendar Watch - 40.5 mm Gold Case - W1556218

40.5 mm by 13 mm thick 18K gold case, sapphire back, beaded crown set with sapphire cabochon, sapphire crystal, white dial with silvered open-work grid, Roman and Arabic numerals with blued hands, caliber 9422 MC automatic movement with perpetual calendar complication, days indicated by a retrograde hand, months and leap years in a counter at 12 o'clock, black alligator strap with 18K white gold buckle, buckle double deployant. Water resistant to 30 meters.