Zenith Special Aviators' Watch

IWC of Schaffhausen calls itself a creator of the world's first specialized aviator's wristwatch - glorious Mark IX (1936). This claim is arguable to some extent - after all, Longines' Lindbergh Watch was introduced two years earlier, and dozens of other watchmakers supplied military and civil aviators with anti-magnetic chronometers from the early 1920s.
This Swiss Zenith Special (c. 1930) served with the German Luftwaffe. Right before the WWII Zenith chronometers were the French Air Force standard issue.