Among Patek Philippe's perpetual calendars, few are as discreet as the ref. 5039. It was made between 1996 and 2007 and sits in a slim 35.5 mm Calatrava case framed by a Clous de Paris bezel. The design shows that one of watchmaking's most demanding complications can be worn as an everyday dress watch. Inside is the calibre 240 Q, the automatic micro-rotor movement behind some of the house's most celebrated perpetual calendars. It tracks the day, date, month, moon phase, 24-hour indication and leap-year cycle, so it won't need a manual correction until 2100. The 5039 was produced in yellow, white and pink gold, with pink gold the rarest of the three. Phillips estimates that only around 300 pink gold examples were made. Key Details Patek Philippe Perpetual Calendar ref. 5039R 18k pink gold case, 35.5 mm Clous de Paris hobnail bezel Silvered dial with applied gold indices Automatic calibre 240 Q with micro-rotor Perpetual calendar, moon phase, 24-hour and leap-year indications.