In 1999, IWC introduced the Da Vinci Tourbillon. This version of the Da Vinci Perpetual Calendar features a hand-wound movement with tourbillon escapement, while maintaining the same size as the original 1985 model. The watch was offered in yellow gold (200 pieces) or platinum (50 pieces), as well as a limited edition yellow gold 'Four Seasons' model with an engraved dial (20 pieces) and a 'Leonardo' model in yellow, rose, and white gold (50 pieces each). The dial could be marked in German, Italian, English, or French, although this may not be visible in our images. The Da Vinci Tourbillon reference IW3752-18, part of