-- The Rolex Explorer II was first introduced in 1971 with the reference 1655. The model provided a completely new configuration, with the absence of the traditional 3-6-9 “Explorer” dial configuration, an enlarged 39mm diameter Oyster case, date aperture, with a 24-hour bezel. Finally, a large orange 24-hour hand used with the 24-hour bezel permitted the exact hour to be read at a glance, and led to its Italian nickname “Freccione”, meaning "big arrow". Designed for explorers (unsurprisingly) and professionals alike, it specifically targeted speleologists as the large orange luminous hand is intended to be visible in the low light conditions of a cave allowing the wearer to track the day/night cycle in case of prolonged underground expeditions.
-- The reference 1655 was in production through the mid-1980s and released with a total of five different dial types. The present watch displays the “Mk 4” dial with “T SWISS < 25T” with serif font, which is correct for the serial number. The present watch is nicely preserved and a prominent yet uncommon model within the Rolex product line since it was first introduced.