Jim Sturgess wears a Rolex Submariner

Halfway through Robert Luketic's 21 (2008), Ben Campbell is no longer the shy MIT engineering student we met at the start. He is at a Las Vegas blackjack table, sleeves of his jacket pushed back, his teammate Jill Taylor (Kate Bosworth) seated beside him with a drink, and the casino's security chief Cole Williams (Laurence Fishburne) leaning low over the felt to watch his hands. The film, adapted from Ben Mezrich's Bringing Down the House, follows the MIT Blackjack Team as a band of students counts cards across the Strip; Kevin Spacey plays the professor who recruits them. The scene is the high-roller version of Ben, the one with stacks of blue and white chips in front of him and a man twice his size breathing down his neck.

On Ben's left wrist, resting at the edge of the table beside those chips, is a steel dive watch. It has a black rotating bezel with a lume pip at twelve, a black dial with applied round markers, a broad hour hand, a date window at three, and a steel three-link bracelet. The silhouette is the one every casual watch fan recognizes on sight, a Rolex Submariner. The dial text does not resolve cleanly in the frame, so the exact reference stays open, but the configuration is unmistakable.

There is a small joke buried in the choice. The Submariner was built to keep working three hundred meters underwater, and Ben will never get it anywhere near water. The only deep end in this story is the casino floor, and the only thing closing over his head is Fishburne.