Who would have imagined that IWC would be the second brand to introduce a serially produced perpetual calendar chronograph wristwatch, following https://www.crwwatches.to/Collection/panthere-de-cartier/ Patek https://www.iwuhren.de/produkt-Sammlungen/aquatimer/ Philippe's introduction of the model in 1941? Forty-four https://www.iwhorloges.cz/ years would pass until IWC launched its innovative and outstanding Da Vinci Chronograph ref. IW3750 in 1985.