A new chapter of the storied history of the Rolex Explorer opened with the release of the Explorer II in 1971. Just like its older sibling, the Explorer I, the Explorer II was a sturdy steel toolwatch but bigger and more outspoken. While its smaller brother sat on the wrists of mountaineers, the Explorer II was designed for the men and women that ventured into the deepest caves and across the far poles. As it is difficult to distinguish between day and night in these places, the watch features an extra hour hand and a fixed 24-hour bezel so that you can always read the correct time.