F.P. Journe Classique Quantième Perpétuel Platinum 40 MM - Black Leather Strap - Silver Dial - Quantième Perpétuel

40 mm, Platinum case. "Quantième Perpétuel" refers to a perpetual calendar, and here's a description of the F.P. Journe Quantième Perpétuel:

Optimum readability and simplified use for the F.P. Journe Quantième Perpétuel with instantaneous jump. During the 18th century, astronomical watches gradually gave way to the manufacturing of watches showing the date and, usually, the moon phases. These primitive calendar watches were all of the simple calendar type, meaning that at the end of each month of less than 31 days, the days hand had to be put forward manually. Adding to the movement the complicated mechanism of a perpetual calendar, in which, every four years, the 29th of February would be automatically recorded, had long been the dream of every watchmaker. The F.P. Journe Quantième Perpétuel (perpetual calendar) displays the exact date by automatically taking into account the variable length of the months and leap-year cycle. It also displays the day, month, and often the moon phases.

F.P. Journe Classique Quantième Perpétuel Platinum 40 MM - Black Leather Strap - Silver Dial - Quantième Perpétuel