The Rolex Milgauss series of antimagnetic certified chronometers was first manufactured in 1954 with the model 6541 for those working in nuclear, aircraft, and medical settings associated with strong magnetic fields. The watch has an advertised magnetic flux density resistance of 1,000 gauss within magnetic fields of 80,000 A/m. In 2007, after being out of production for nearly two decades a new Milgauss was introduced as the model number 116400.