The GMT Master was created by Rolex in the second half of the 1950s in collaboration with Pan Am and issued by the airline to its crews on long-haul flights enabling them to read a second time zone on their timepiece.

The present example for the early 1980s is differentiating itself from its original version with a number of improvements, notably the crown guards and the quick-date set mechanism. The bronze colored dial has never been touched, but displays a fascinating lava red discoloration process around its hour markers, from where its nickname "volcano" dial stems. Another particularity of this watch is the capital "F" added to its 16573 reference number, something we do not recall having seen on another example of this reference.

Extensive research results in a theory that states that this letter was engraved so that at the Rolex assembly line, the watch makers would know on which cases 14 karat or 18k karat gold bezels had to be mounted. Lastly, the caseback is inscribed "acier inox - stainless steel - registered design", an inscription normally associated to ladies watches of the same period.

The present lot in steel and gold attire complemented with a fascinating brown dial and caramel and chocolate bezel (also called root beer bezel by collectors) is a flamboyant example of the exuberance of the 1980s. In overall excellent condition with the particularity of having the case back stamped this lot would interest the collector interested in a GMT Master with a twist.