Oakley Holeshot - Eric Christian Olsen - NCIS: Los Angeles
The watch worn by Eric Christian Olsen is first seen in the beginning of the fourth season of NCIS: LA which aired in 2013 and clearly visible in the season finale, episode 24 "Descent" of season 4. The watch is a Oakley Holeshot® Stealth, with black rubber strap, black dial, black 47.5mm case, modelnumber 10-228.
Holeshot® is engineered with a true Swiss Made chronograph that measures cumulative time, intermediate time and split time down to a tenth of a second.
The band is made from Oakley's Unobtanium® (a material which has the unusual property of increasing tackiness and thus grip when wet).
The same model watch is also worn in the series Graceland, by actor Daniel Sunjata.
Thanks to Alec for the ID