IWC Big Pilot's Watch Perpetual Calendar IW503605

The perpetual calendar, invented for IWC by watchmaker Kurt Klaus, is one of the most appreciated complications ever. Moreover, Klaus's does not need correction until 2100, when the leap year is not included due to an error in the Gregorian calendar. Thus, this perpetual calendar with its patented double moon phase can correctly identify every day of the week, even if it is February 29. The 7 days power reserve of this automatic calibre is essential to the calendar's function, you don't have to think about winding it too often. The blue calfskin strap complements the dial with the power reserve indicator, the 46.2 mm case is made of steel, the dial is sapphire glass.