The layout of the 5396R-012 is a classic calendar arrangement that can trace its history back to the days of pocket watches. The month and day are visible through two apertures towards the top of the dial at the 6 o'clock position is the moon phase 24 hour indicator and date aperture. The 324 self winding movement is housed in a perfectly proportioned 38.5mm diameter case. With 2016 marking the 20th anniversary of the annual calendar Patek decided to commemorate the occasion with a special dial. Shown here in rose gold with the anniversary silvery opaline dial with Breguet numerals perfect for formal or casual occasions.