The reliability and precision of an ordinary mechanical watch can be affected by a magnetic field of 50 to 100 gauss. But many scientists are exposed to much higher magnetic fields during the course of their work. Rolex’s solution was the Milgauss, created in 1956, the first watch of its kind. Hence the name of the watch, mille being French for thousand.The reference 116400 was introduced in 2007. The black dial model (non-GV) was discontinued in 2013. The Z-Blue version was added in 2014.
