Rolex introduced the Explorer II series in 1971 as an addition to the 1954 Explorer. It features an additional 24-hour indication that can also be used as a second time-zone. This 24-hour indication, among other things, has been designed with regard to professional cavers, for whom a reliable temporal orientation independent of the outside world is of the utmost importance. Accordingly, at the design of the dial a special emphasis was put on excellent readability, even in the dark. In contrast to the GMT-Master or the Submariner, the bezel of the Explorer II does not rotate, but is fixed and has a scale of 24 hours.
This original Explorer II uses a 39 mm case very similar to the contemporary GMT-Master Ref. 1675. In keeping with its sporting intent, it used an Oyster bracelet and featured crown guards. The bezel is marked with numerals at even numbers between 2 and 24 and bars between. The dial features many lume markers, with a large triangle at 12 00, large bar markers at 6 00 and 9 00, smaller bars at the other hours, and square markers outside the marker circle at the half-hours. There is a date window at 3 00 with a cyclops magnifier. The hands are simple sticks, with the 24 hour hand being a thick orange or red arrow.
The 24 hour hand gives this model its nickname. This original Explorer II reference is sometimes called “Freccione”, meaning “arrow” in Italian. Although only the earliest Explorer II models have a true orange hand, the red hand on later examples has usually faded to an orange color as well. Although there is no record of him wearing this reference, the watch is also sometimes called a “Steve McQueen”.
The Explorer II is powered by the self-winding movement Cal. 1575GMT, shared with the GMT-Master Ref. 1675. In contrast to later models, the 24 hour hand is not independently adjustable. Since the bezel is also fixed, this means that the Ref. 1655 Explorer II is not a GMT or second timezone watch.