Notes: A popular nickname of the Explorer II ref. 1655, is the erroneous “Steve McQueen Rolex” label. There actually isn’t any photographic evidence that Steve McQueen ever sported an Explorer II, but rather, his Rolex of choice was a Submariner. Nevertheless, the Explorer II ref. 1665 will forever be known as the Steve McQueen!

Mechanism: The 1575 is the date version of the 1570. Like many rolex movements the date version will be stamped with the same number as the non-date version. Hence you will see "1570" stamped into most (if not all) 1575 movements. The sure fire way to tell the difference is the presence of the date wheel.

The 1570 movement superseded the 1560, but shared the vast majority of its elements, with a few notable improvements. The 1570 marked the third generation of the 1500 series. It comes with the balance assembly Rolex p/n 8106, again with a Breguet hairspring. However, it’s with a higher frequency of 19,800 bph, or 2.75Hz.

Similarly to its predecessor, Rolex also manufactured it as a date and GMT version, the 1575, which proved the perfect companion to the Explorer II released in 1971, as well as the GMT-Master and Datejust series. As with many of the date equipped mechanism made by Rolex, the number stamped into the metal is the NON-date version. Hence in the case of the 1575, the mechanism will be stamped "1570".

Although there is no Quickset mechanism, the 1500 calibers came with the cam and jewel system. This system was able to create an instantaneous date change at midnight, still used by Rolex today.

Family Notes: Rolex introduced the Explorer II in 1971. This watch was not a successor of the Explorer 1016, but an additional timepiece with an additional function. The Explorer II was aimed at speleologists or cave explorers, who could lose sense of time during their work. The Type II came with the additional (24) hour hand, 24 hour scale bezel and a date. The Explorer II (like the I) is a chronometer and the cases were designed to handle 100m water resistance. You only had to open a National Geographic Magazine of the 1970’s and you’d see an Explorer II ad inside.