The IWC GST Perpetual Calendar Chronograph (Ref. IW375603) is a highly complex sports watch from the early 2000s, notable for merging the mechanical sophistication of Kurt Klaus’s perpetual calendar module with a robust titanium construction.

• Case & Material: 43mm diameter and approximately 16mm thick, crafted entirely from titanium, making it significantly lighter and more comfortable than its stainless steel counterpart.

• Movement: Powered by the IWC Caliber 79261 (based on the Valjoux 7750), featuring a self-winding automatic movement with a 44-hour power reserve.

• Complications:

  • Perpetual Calendar: Automatically adjusts for leap years and varying month lengths until the year 2100.

  • Chronograph: Integrated stopwatch functionality.

  • Four-Digit Year Display: A signature IWC feature located between the 7 and 8 o’clock positions.

  • Moon Phase: Highly accurate moon phase indicator at 12 o'clock.

• Dial: Deep black dial with high-contrast luminous hands and indices for superior legibility.

• Water Resistance: Rated to 120 meters (400 feet), which is exceptional for a high-complication perpetual calendar.

• Bracelet: Features IWC’s patented integrated titanium bracelet system, which can be sized using a simple tool (often just toothpicks) by releasing spring-loaded buttons on each link.