Portugieser Perpetual Calendar ready for centuries of dates, moons, and moments.

44 mm of clever. Portugieser Perpetual Calendar ready for centuries of dates, moons, and moments. Elegant, smart... and maybe a little smug. IWC Engineer Christian Satzke explains how it works. And for those wondering what happens in 2299: some of our Perpetual Calendar models also feature an additional century slide. Once installed inside the movement, it extends the mechanism’s accuracy by another two centuries, allowing the watch to display the correct date all the way until the year 2499. Making it, well… even more perpetual.