No other complication has appeared on the Big Pilot's Watch face as often as the perpetual calendar. Developed in the early 1980s by IWC's then chief watchmaker, Kurt Klaus, the large dial not only lends itself well to housing this mechanism, but also makes it particularly easy to read. The Big Pilot's Watch Perpetual Calendar features a steel case, blue dial, rhodium-plated hands, and blue calfskin strap. The perpetual calendar automatically recognizes the lengths of different months and leap years and requires no manual adjustment until 2100. Constructed from around 80 individual components, the calendar module is driven by a single nighttime switching pulse of the in-house caliber 52615 IWC. The highly stressed components of the Pellaton system are made of virtually wear-free ceramic. When fully wound, the two barrels accumulate a power reserve of seven days. The elegantly decorated in-house movement is visible through the sapphire crystal caseback.