In 1985, IWC unveiled the Da Vinci Perpetual Calendar, featuring a revolutionary perpetual calendar mechanism. This mechanism became a bestseller and was used in various IWC watches, as well as models from other brands like JLC. The Da Vinci Perpetual 3750 came in a 39mm polished Red Gold case with a Black dial and contrasting sub dials. It was also available in different metals and dial colors, with the option for a sapphire crystal. The newer 3758 model was introduced around 2005. The original versions used the caliber 7906(0) movement, which was later updated to 79061 and then 79261.