This model of Ref. 6541 was specially made with an inclined polished bezel for the American market instead of a graduated black revolving bezel, to avoid confusion between the Milgauss and Submariner models.
The Milgauss was introduced in 1954 for use in high magnetic fields. It was primarliy created for people working on scientific experiments or in power stations, who would need a watch that remained accurate in conditions of work where high magnetic fields existed.
The watch's distinctive name was derived from the French word 'Mille', meaning thousand, and 'Gauss', which is a measurement of magnetic induction. Magnetic fields affected the balance workings of a watch. A normal watch will become erratic at 60 oersted and cease to fundtion at around 100 oersted. The Milgauss had anti-magnetic alloys in parts of its movement, which was encased by an iron shield, thereby enabling the watch to remain accurate in fields of over 1000 oersted. At the time of its launch the Milgauss was considered a marvel of horological engineering. Not only did the watch function perfectly when subjected to a magnetic field of 1000 oersted (its guaranteed limit), but it could also remain accurate at 5000 oersted. In fact, even after being placed in such powerful magnetic fields, the residual magnetism in the watch's workings was insufficient to affect its accuracy. It would seem that none of the Milgauss models were ever great sellers. The Milgauss had a small professional market, and its other buyers would probably have just liked the look of this large-case watch, and never required its unique anti-magnetic features. The Milgauss was finally withdrawn from the Rolex catalog in 1988, although for a short time afterward it was still available as a special order piece. In 2007, Rolex reintroduced the updated and evolved Milgauss; now its target market is listed as "medical imaging".
This beautifully preserved example has a wonderful aged tropical dial and is the rare version that does not feature the word "Milgauss" on the dial. The owner purchased an extra revolving bezel that allows the wearer to have both versions of the 6541, one of the most iconic sports watches ever made by Rolex.