The Rolex Explorer II was presented by Rolex in 1971 as an addition to the 1954 model Explorer I. 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 for professional cavers, for whom a reliable temporal orientation, independent of the outside world, is of the utmost importance. In addition the design of the dial puts a special emphasis on excellent readability, even in the dark.
In contrast to the GMT-Master or the Submariner, here the bezel does not rotate, but is fixed and has a scale of 24 hours. The watch is optionally available with a black or a white dial.
Rolex produced the initial Explorer II until 1984. It featured Cal. 1575GMT, like the similar Rolex GMT-Master, and a 39 mm case. The orange-tipped 24-hour hand is the signature feature; although later models had a red hand, which faded to orange over time though. This model is sometimes called the "Freccione" ("Arrow" in Italian) or "Steve McQueen", even though there is no evidence that the actor ever wore this model.
A transitional model Explorer II, was produced from 1985 till 1988. It is similar to the previous model but uses the new Cal. 3085 with an adjustable GMT hand from the Rolex GMT-Master II. The case is larger as well, at 40 mm.
The modern Explorer II, was introduced in 1989. It uses the new Cal. 3185, still with the adjustable GMT hand and fixed bezel. This was produced for over 20 years, upgraded to Cal. 3186 and the "ROLEX ROLEX" rehaut in 2007.
The latest Explorer II was introduced in 2011, it uses Cal. 3187 and features a larger 42 mm case. The Explorer II is available with either a black or a white dial, both in stainless steel with the Oyster bracelet.