The Portofino Perpetual Calendar features the legendary perpetual calendar developed by Kurt Klaus during the 1980s. At 40 millimetres, the Portofino Perpetual Calendar is the smallest perpetual calendar in IWC's portfolio. This version features an 18-carat 5N gold case, a silver-plated dial, and gold-plated hands and appliques. IWC's legendary perpetual calendar was originally engineered during the 1980s by the brand's former head-watchmaker, Kurt Klaus. The ingenious mechanism is mechanically programmed to recognize the different lengths of the months as well as the leap years. It will run without any adjustments until the year 2100. The calendar information is displayed in three subdials at 3, 6, and 9 o'clock. Made of solid gold, the moon phase disc shows the moon against the backdrop of a star-studded night sky. Thanks to a special reduction gear train, it is so precise that it will only deviate by one day from the orbit of Earth's satellite after 577.5 years. Through the transparent sapphire glass back, one can catch a glimpse of the IWC-manufactured 82650 calibre. Engineered with a focus on robustness and precision, this high-end automatic movement features IWC's Pellaton winding system, which has been reinforced with ceramic components and builds up a power reserve of 60 hours. This exclusive timepiece is fitted with a blue calfskin strap with a butterfly clasp.