Hans Wilsdorf loves exploits, as evidenced by the Rolex watches that have equipped many adventurers. He designed and manufactured the Explorer I for Sir Edmund Hillary who decided to climb Mount Everest, "the roof of the world", at an altitude of 8,848 m. Designed to withstand all kinds of challenges, it is robust, reliable, readable and precise. It raises the brand to the rank of iconic myth-maker: a true legend is born, and the manufacturer strikes hard with this historic model.

Then Rolex launched production of the Explorer II in 1971 with the reference 1655. Instead of presenting an improved version of the Explorer I, a brand new model was introduced. A 24-hour steel bezel with a 24-hour scale allows the explorer working underground, mainly speleologists, to distinguish between day and night.

In 1985, the reference 16550 was launched to replace it, and staid in production until 1988. This transitional ref. 16550 had a larger case (40 mm.), a sapphire glass and the 3085 caliber. Without the orange freccione, the dial is more conventional. However, the beautiful homogenous “ivory” patina of this present example is highly sought after by collectors nowadays. For the first time, the 24 hour hand is independently adjustable, thanks to the new cal. 3085. This means that the Explorer II can now display a second time-zone.