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 adjust...