With Rolex after-sale service invoice dated 21 December 1981 and presentation box.
The present watch is an exceedingly rare and early example of the Milgauss model introduced in the mid-1950s. It stands out by virtue of its beautiful and rare honeycomb dial and red-tipped sweep center seconds hand. Reference 6543 was the very first Milgauss to be launched, but was very soon replaced by reference 6541, which features the famous flash sweep center seconds hand.
The main two elements which differentiate reference 6543 from its successor are the width in between the lugs, here 19mm and then later changed to 20mm, and the "soft" case back which one can only feel when gently pressing on it. Furthermore, the reference number inside the case back is not stamped but rather engraved. The hands on the present were most likely replaced during a servicing in 1981 and were taken from the reference 1019 Milgauss series - the model which was then in production. This example here has survived in otherwise incredibly original condition and impresses its beholder with sharp case lines, crisp numbers in between the lugs and an untouched dial.
Today, only a handful examples of this rare model are known amongst collectors and examples coming in such unspoilt condition are amongst the rarest finds for collectors.
The Milgauss was designed for use in areas of high electro-magnetic radiation, such as research labs or power stations. The influence of radiation on the balance work results in losing accuracy. These effects can be reduced by using the principles of a "Faraday Cage", e.g. by placing the movement in an iron inner case shielding the movement.
The Faraday Cage is attributed to the physicist Michael Faraday who, in 1863, built a room coated with metal foil and allowed high-voltage discharges from an electrostatic generator to strike its outside. He then used an electroscope to show that there was no excess electric charge on the inside of the room's walls.
Ref. 6543 is mentioned in 100 Years of Rolex, 1908-2008 by Franca and Guido Mondani, p. 67. Meanwhile, a reference 6541 is illustrated in 100 Superlative Rolex Watches by John Goldberger, pp. 224 & 225, and in I Cronografi Rolex - La Leggenda, Pucci Papaleo Editore, p. 33.