Rolex GMT-Master II

The Rolex GMT Master was developed by Pan Am Airlines for airline pilots in the 1950's. This model was the first to introduce the "dual time zone" feature, which was designed to reduce the impact of jet lag. The original 1955 model (reference 6542) had a graduated disc with two colors: red for daytime and blue for nighttime. The second time zone is read with a triangular hand that makes a full 24-hour revolution. This model was mostly made of steel, although there are also yellow gold variants that have different details. Between 1989 and 2005 we had the Rolex GMT Master with reference 16713. This watch had been made with two materials, 18 carat gold and steel. The bezel comes in two versions, black and the second one is half gold and bronze. There is a third version in which the dial has 8 diamonds in place of the indexes. Until the late 90's there was the phrase "SWISS-T <25" which indicates that the material of the indexes and hands is tritium, also, at the same time, the plexiglass is changed by sapphire.