The Ingenieur Perpetual Calendar 41 is the first stainless steel model to combine Gérald Genta’s visionary Ingenieur design with Kurt Klaus’ crown-operated perpetual calendar. The watch features a 41-millimetre case and integrated bracelet made of stainless steel, a blue dial, and rhodium-plated hands and appliques. Seamlessly integrated into the case via a middle-link attachment, the H-link bracelet with a butterfly clasp ensures excellent wearing comfort. The characteristic bezel, a hallmark feature of Gérald Genta’s design, is secured to the case with five functional screws. The case and bezel are elaborately finished with a combination of satin-finished and polished surfaces. The H-links of the bracelet are satin-finished with polished outer edges, while the middle links and the case back ring are polished. Another highlight is the dial with the characteristic «Grid» pattern, consisting of small lines and squares. It adds additional depth to the dial and reflects the light exquisitely. The subdials displaying the calendar information are treated with a sunray finish, while the outer edges feature a refined «azurage». The rhodium-plated metal markers and the hands are filled with Super-LumiNova®. The perpetual calendar displays the date, day of the week, month, and moon phase on the dial. Thanks to a reduction gear train using two intermediate wheels, the moon phase display will only deviate by one day after 577.5 years. In addition to showing the day of the week, the subdial at 9 o’clock also features a small leap year indicator, which counts down the years to the next leap year. The IWC-manufactured 82600 calibre features a Pellaton winding system. Equipped with components made of virtually wear-free zirconium oxide ceramic, it reliably builds up a power reserve of 60 hours in the mainspring. The movement is finished with circular graining, Geneva stripes and blued screws and can be observed through the sapphire glass case back.