This is a tropical example of a Ref. 145.013 Omega Flightmaster. These watches were distinct for their GMT function, and inner rotating bezel.
This watch is in good vintage condition, and the dial has aged to a “tropical” brown-grey. The dial has some light blemishing between the 11 and 12 markers. The case is in great condition. The watch is also fitted on the original bracelet, with correct endlinks.
For some more great reading on these historic watches, head on over to Chrono Maddox here.