The Tourbillon Rétrograde Chronograph is the highest-priced watch in the new Da Vinci collection by IWC, and it includes three complications: tourbillon, chronograph and retrograde date. It is powered by the new in-house 89900 calibre, self-winding, running at 28,800 vibrations per hour, 4 Hertz. It has some significant technical features. Advanced materials in the 89900…