IWC Watch Portofino Hand Wound Eight Days IW510103. In the Portofino Hand Wound Eight Days, the IWC manufactured 59210 calibre movement will run precisely and reliably for a full 192 hours, or 8 days, before it automatically stops. Strictly speaking, it is 9 days, but the extra day in reserve ensures that the movement maintains as constant a driving torque as possible and continues to run precisely. The owner will always be on the safe side if he winds his watch once a week. The power remaining can be read off on the power reserve display on the dial. Together with the small seconds display and date display, this gives the dial a pleasing equilibrium. The indexless balance has a frequency of 28,800 beats per hour and, together with the Breguet spring bent into shape in accordance with age old watchmaking tradition, helps to make the watch exceptionally accurate. The watch is available with a stainless steel case, silver plated dial and solid gold indices. It has a transparent sapphire glass back and a brown alligator leather strap from the House of Santoni.