Realized by using a pocket watch reference 5301 with calibre 9720 of IWC. "Flying" tourbillon, containing 5 main parts made of polished steel and brass, on ball bearing. Monometal balance with Breguet-overcoil. Three-quarter-plate with gold chatons. Power reserve indication without differential at the movement side. This design is still the base of the "Stiftentourbillon" in IWC's own watchmaking shool. Satinated stainless steel case with crystal caseback.