In the movie Mission: Impossible II (2000), the lead character Ethan Hunt (played by Tom Cruise) wears a Casio G-Shock DW6900-1V.

The watch was actually a prop, with a digital screen. The prop doesn't have the Casio, G-Shock and G markings, see the images. Also, extra 'features' have been added to the digital screen, which on the actual watch don't exist.

One of the prop watches was on display in New York City during a promotional tour for Mission: Impossible - The Final Reckoning. See the image taken from a Bond Experience video of the exhibit.

This G-Shock watch features shock resistance, 200M water resistant, countdown timer, 1/100 sec. stopwatch and auto-calendar. The watch in the film has a black resin band with neutral face (model number 1V) but is also available in other colors.

The Casio G-Shock DW6900 watch is still popular and widely available:

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In the first Mission: Impossible film, Ethan Hunt wears another Casio, the DW290-1V, and in the next movie Mission: Impossible III, he wears a Casio G-Shock MTG910DJ.

Complete the look
Ethan Hunt wears a pair of Oakley Romeo sunglasses in Mission: Impossible II.