Chris O'Donnell wears a MTM Silver Silencer

Callen does not have a first name, or rather he spends most of NCIS: Los Angeles not knowing what it is, a foster-system kid who moved through thirty-seven homes and grew into the agency's deep-cover specialist. Chris O'Donnell played him across all fourteen seasons as a man more comfortable being other people than himself, the restless half of his partnership with LL Cool J's Sam Hanna. Where Sam is settled, Callen is always slightly somewhere else.

The watch is the MTM Silver Silencer, the brushed-steel version of the Silencer made by MTM Special Ops, a small Los Angeles outfit that builds tactical LED watches. By MTM's own account the company put O'Donnell in the Silver Silencer and gave LL Cool J the blacked-out Black Vulture. Its 316L steel case, 44.5mm without the crown, runs ordinary analog hands over a digital display that stays dark until a button wakes it, and it sets two white LEDs in the case for a flashlight and an emergency strobe. It is water resistant to a hundred meters, and nothing about it asks for a battery change: a rechargeable cell rated for roughly ten years tops up on an induction pad, the way a phone does. MTM still sells the steel version for around twelve hundred dollars.

The silver finish suits Callen better than black would. He is the one who blends in, and a watch that passes for an ordinary steel sports watch until someone presses the button is about as undercover as a watch gets. MTM has put the same Silver Silencer on other actors too, Bill Pullman among them in American Ultra in 2015.