The Portugieser Hand-Wound Tourbillon Day & Night features an 18-carat Armor Gold® case with a diameter of 42.4 millimeters, an Obsidian lacquered dial, gold-plated hands and gold appliques. Thanks to its improved microstructure, Armor Gold® is significantly harder and more wear-resistant than conventional 5N gold alloys. The black and highly polished dial radiates a tremendous depth and creates a beautiful contrast. The flying minute tourbillon at 6 o'clock is one of the most sophisticated complications in watchmaking. The tourbillon places the balance wheel and pallet lever inside a small cage that rotates around its axis once every minute. The pallet lever and escape wheel are made of silicone and treated with a special diamond coating. This Diamond Shell® technology reduces friction and improves the flow of energy in the movement, contributing to the high-power reserve of 84 hours. Thanks to the integrated tourbillon stop, the mechanism can be brought to a complete stop and the watch set with down-to-the-second accuracy. Another highlight is the innovative day and night display at 9 o'clock, which shows the eternal cycle of day and night with the help of a little planet rotating around its axis. As the movement is hand-wound and has no oscillating mass, the small globe is visible from the front and back. The idea for this unique concept came from an IWC apprentice watchmaker. The Portugieser Hand-Wound Tourbillon Day & Night is powered by the IWC-manufactured 81925 caliber, which is elaborately finished with circular Geneva stripes. The gold-plated base plate is partly skeletonized to offer an unimpeded view of the barrel and other components. The watch is fitted with a black alligator leather strap from Santoni with an 18-carat Armor Gold® folding clasp.