The IWC Aquatimer Chronograph "Tribute to Calypso" (Reference IW378203) is a highly collectible, 2,500-piece limited edition dive watch released in 2008. It was crafted by IWC Schaffhausen as a tribute to oceanographer Jacques-Yves Cousteau and his legendary research vessel, the Calypso. Portion of the original sales proceeds went directly to the Cousteau Society to support the salvage and restoration of the ship.

• The Caseback: The solid stainless steel caseback features a detailed 3D engraving of the RV Calypso and its limited edition number (e.g., XXXX / 2500). 

• The Bezel Glow: Unlike traditional dive watches with external bezels, this model features an inner bezel protected under the sapphire glass. The entire 15-minute dive scale is heavily coated in Super-LumiNova for high visibility underwater. 

• Reference Distinction: Do not confuse this version (Ref. IW378203) with the earlier Ref. IW378201. While both were limited to 2,500 pieces, the older 2006 variant (IW378201) actually had a literal slice of original wood from the Calypso embedded directly behind the caseback sapphire window. The IW378203 relies on an all-steel stamped artistic image of the vessel.

• Case Diameter: 44 mm

• Case Thickness: 15.5 mm to 16 mm

• Lug-to-Lug Distance: 51 mm

• Case Material: Brushed and polished stainless steel

• Dial: Deep navy blue with a unique multi-tone layout (black subdials, yellow and white accents)

• Bezel: Internal unidirectional rotating dive safety bezel (operated by the dedicated crown at 4 o'clock)

• Crystal: Scratch-resistant sapphire crystal

• Movement: Automatic IWC Caliber 79320 (highly modified Valjoux 7750 base)

• Power Reserve: 44 hours

• Complications: 12-hour Chronograph, Day, and Date apertures at 3 o'clock

• Water Resistance: 120 meters (12 ATM / 400 feet)

• Strap: Integrated black vulcanized rubber strap with a steel tang buckle