The Rolex GMT-Master ref. 1675 introduced in 1959 and discontinued 21 years later in 1980, is viewed by collectors as the archetypal GMT-Master. Of course, it wasn’t the first GMT-Master to be produced, but it was the reference that established the GMT-Master within the public conscience as a worthwhile tool watch to own. With its long production run, the ref. 1675 has been subject to numerous changes throughout its lifetime, some minor and some rather major. The entire reference itself, however, built upon the earlier ref. 6542 with some significant differences. The ref. 1675 came with an improved aluminium bezel insert which replaced the previous material, Bakelite. The second change was the introduction of crown guards, together with the new bezel, the ref. 1675 is a far more robust timepiece than its predecessor.