The Rolex GMT is the jet-setting icon of the Rolex sports watch family. Like the Rolex Submariner, the Rolex GMT is sophisticated, rugged, and versatile. In 1954 Pan Am started using the newly designed Boeing 707 which allowed for Pan Am to fly transcontinentally and is said to have started the commercially available jet age. In the same year, Rolex received a request from Pan Am to create a technical pilots watch which indicated two time zones simultaneously that could be issued by the airline to their crews on long-haul transcontinental international flights. GMT or UTC stands for Greenwich Mean Time or Coordinated Universal Time which is the primary time standard by which the world regulates clocks and time. GMT or UTC is the time zone that is required for all aviation planning, weather forecasts, schedules, and other paperwork. The original Rolex GMT Master has a fourth 24-hour hand directly displaying the same time zone as the standard 12-hour hand but on a 24-hour scale. This GMT hand enabled the crews to set the watch to GMT or another time zone, and, using the rotatable 24-hour scale bezel, set to the correct offset thus displaying a second-time-zone on the 24-hour scale. This specific 1979 Rolex Two-Tone GMT Master Ref. 1675 is an excellent watch for the seamless switch from formal to casual making it the perfect daily driver for the businessman always on the go. The other convent feature of the ref 16753 is the quick set date feature of the Rolex 3075 caliber movement. Stock # RLX1675GMT80TT Brand Rolex Style GMT Master Model 16753 Serial 63XXXXX Size Men's Material SS/ 14K YG Dial Gloss Black "Nipple Dial" Millimeters 40mm Strap Rolex Two Tone Jubilee 14K YG CASE & BRACELET The case of this 1980 Ref.16753 has previously been polished but retains thick and full lugs. The 14k YG bezel is free of any dents or dings and matches the overall feel and condition of the watch. The watch comes supplied with a Rolex 62523 two-tone jubilee bracelet that shows normal stretching retains 18 links and original 450 end links DIAL & HANDS The original gloss black nipple dial remains in wonderful condition. The tritium dial and hands have achieved a sought after creamy patina and show no lume degradation when viewed under U.V. light. ACCESSORIES The watch just received a full service and comes backed by a 1-year warranty on accurate timekeeping.