Which Rolex sports watch was designed for explorers and introduced in 1953?

The Rolex sports watch designed for explorers and introduced in 1953 is the Rolex Explorer.

Rolex developed the Explorer after the successful ascent of Mount Everest by Edmund Hillary and Tenzing Norgay in 1953. Watches associated with the expedition helped Rolex promote the idea that its timepieces could withstand extreme environments, although the exact watches used during the climb and their relationship to later commercial Explorer models are often simplified in popular accounts.

The Explorer became known for its highly legible black dial with prominent Arabic numerals at 3, 6 and 9, plus luminous hands and markers. Its relatively restrained design distinguishes it from Rolex’s dive watches and chronographs. The model was intended for readability and robustness rather than a complicated display.

The Explorer is sometimes confused with the Air-King because both are Rolex sports-oriented watches with simple dials. It is also separate from the Explorer II, introduced in 1971 with a 24-hour hand for cave and polar exploration.