IWC IW503502 is one of the most complicated and difficult to reproduce stIWCes. The soul of this watch is the movement. It also has month, calendar, day of the week, small seconds, kinetic energy display, automatic 7-day energy storage and battery life automatic mechanical movement -52850 self-produced movement (the previous ones on the market are fake months, Holiday week, which means that the month and week will not move). The factory did not hesitate to spend tens of millions of dollars, which lasted for 3 years, and combined 5 movement factories for research and development. After 19 failures, more than 30 modifications and adjustments, the 52850 movement with the same function was finally cloned, and the case work was the same as the previous one. The V4 version is more delicate, which can be described as painstaking.