The IWC GST Perpetual Calendar Chronograph (Reference IW375618) is a highly collectible luxury sports watch produced by IWC Schaffhausen from roughly 2001 to 2004. This particular reference combines a robust 43mm stainless steel case with a clean white dial featuring Italian text markings on the calendar sub-dials.

• Movement: IWC Caliber 79261 (Automatic mechanical movement heavily modified from the reliable Valjoux 7750 base). 
• Case Dimensions: 43mm in diameter and 16mm in thickness. 
• Complications:
  • • 12-hour Chronograph (Stopwatch)
    • Perpetual calendar (Tracks days, dates, months, and a full 4-digit year window)
    • Perpetual moon phase display 
• Dial Variations: The IW375618 features the white dial configured in Italian. Separate reference numbers exist for English (IW375619) and other languages. 
• Bracelet: Integrated modular stainless steel bracelet with a tool-free pin release system for effortless resizing. 
• Water Resistance: Substantial sports watch protection up to 120 meters (400 feet). 
• Crystal: Scratch-resistant, non-reflective convex sapphire crystal.