Matthew Fox, as Dr. Jack Shephard in the television series Lost, wears a Porsche Design Quartz Chronograph P10 ref 6600.41.10.134. The watch can briefly but clearly be seen in Episode 5 of Season 6.

The Porsche Design Quartz Chronograph P10 seen in Lost has a silver/white dial, red seconds hand, date window at the 4 o'clock position and steel band.

In previous seasons of Lost, Jack wears different, but unidentified watches.

Thanks to Alan F, aBlogtoRead, and watchfinder.co.uk for the image of the Porsche Design watch.