Robert Downey Jr. wears a Porsche Design Worldtimer

In Avengers: Age of Ultron (2015), Tony Stark stands in a lab beside Bruce Banner, who hangs back in a white coat while Stark turns a translucent holographic panel in his hands. The watch is on Stark's left wrist: a big round black case, two knurled crowns set close together on one edge, white sword hands, white numerals, and a pale window cut into the black dial.

Identifying it took nine years. In April 2015, days before the film reached American theaters, a fan in France, where it had opened a week earlier, posted a frame of that wrist to a watch forum and asked for help. He apologized for the picture quality and pointed out the problem: the brand is never stated on screen, and the watch never gets a close-up. A reply that same year guessed a Porsche Design world timer, and there the trail sat until a comment in 2024 finally put a full name on it, the Porsche Design Worldtimer P'6750.

The name holds up against the screen. The Worldtimer P'6750 is a 45 millimeter cylinder of titanium, sold bare or with a black coating, and its world-time system accounts for the odd furniture on the dial. Discs rotating behind the dial show a reference city and its local time through two small apertures. Press the button built into the crown at two o'clock and the reference time transfers to the central hands, without the loss of a single second while the change happens. The crown at four o'clock winds the watch and sets the hands, and both crowns carry a clous de Paris knurling that is there for grip as much as for looks. The module behind all this was designed and built by Eterna, Porsche Design's watchmaking partner since 1998, on an ETA Valgranges base, and both versions shipped on a black rubber strap molded on its inner face with a pattern of latitude and longitude lines. Twin crowns, white numerals, a pale dial window, a case that reads black: feature for feature, that is the watch in the lab frame, though the screen never shows a logo.

Off camera the watch changed. During production Robert Downey Jr. posted a photo of himself on the set wearing his own Omega Speedmaster.