IWC 3750 (Pre-owned - Good) — USD 9,450 on eBay

The IWC Da Vinci Perpetual Calendar Chronograph, Reference 3750, represents a landmark achievement in modern horology, introducing a highly integrated and user-friendly perpetual calendar complication to a wristwatch. It was a cornerstone of IWC's offerings in the mid-1980s, showcasing the brand's technical prowess during a challenging period for mechanical watchmaking. The timepiece features a round case, typically crafted from stainless steel, housing an automatic movement. The perpetual calendar module, designed by Kurt Klaus, is notable for its mechanical simplicity, comprising only 81 parts, and its innovative crown-operated adjustment for all calendar displays. This mechanism automatically accounts for varying month lengths and leap years until 2100, requiring no manual correction. For collectors, the Reference 3750 is significant as the debut model for Kurt Klaus's legendary perpetual calendar. It embodies a period of innovation at IWC and remains a highly regarded example of a practical and ingeniously engineered grand complication, celebrated for its historical importance and operational elegance.