IWC timekeepers are pretty sumptuous by nature, but the Portuguese Sidérale Scafusia goes a step further with being the first watch by IWC featuring a constant-force tourbillon, and a modular disc system, providing a customizable rear. Choose from the sky disc, night sky disc, and a myriad different combinations of features, and over 200 different design combinations as you’re offered to choose your own color for the dial, straps inclusively material, case material, and details. However, among the rare constants is the size of 26mm, and the Swiss hand-wind IWC in-house caliber 94900, that runs at 18.000 vph and offers an enormous power reserve of 96 hours.