The Speedmaster Professional X-33, a multi-function quartz chronograph developed in conjunction with pilots and astronauts, passed strict tests to be certified by NASA for 100 Space Shuttle missions. It was the official watch of the MIR space station and has also been chosen as the official watch of the new International Space Station.
Its double case back in titanium makes it possible to reach over 80 decibels for the alarm function, as required for Space Shuttle astronauts.