The IWC Pilot's Watch Spitfire Double Chronograph (Reference IW3718) is a highly collectable, discontinued luxury aviation timepiece famous for its complex "Doppelchronograph" (split-seconds) complication. While standard IWC chronographs measure 41mm or 43mm, this specific double-chronograph generation features an oversized 44mm stainless steel case built to accommodate its highly intricate, layered movement architecture.

• Complication: Split-seconds (Rattrapante / Doppelchronograph) via a dedicated pusher at 10 o'clock to time two simultaneous events. 

• Case Dimensions: 44.0 mm diameter (often misquoted as 43mm due to modern collection standards), 17.0 mm thickness, and a 53 mm lug-to-lug profile. 

• Movement: Automatic IWC Caliber 79230 (29 jewels, 28,800 vph) providing a 44-hour power reserve. 

• Dial: Silvered/silver dial featuring a dynamic sunburst center texture, raised applied Arabic numerals, and contrasting dark grey sub-registers. 

• Calendar Function: Day and date display window positioned neatly at 3 o'clock. 

• Protection: Convex sapphire crystal secured against rapid air pressure displacement, paired with a soft-iron inner case to guard against magnetic fields.