The Cartier Santos 100 Ref W20073X8 features the iconic square-shaped case design with a polished bezel and exposed screws and the large blue spinal crystal cabochon that give Cartier its signature aesthetic.  The Santos was originally produced in 1904 and named after Brazilian aviator Alberto Santos-Dumont.  Santos-Dumont expressed his wishes for a timepiece to be worn on the wrist while flying, in lieu of checking a pocket watch, and Cartier delivered.  Set into production in 1911, the Santos has remained a historic part of the Cartier lineup and remains in production today.