This is an Omega Speedmaster Mark IV automatic chronograph. This ref. 176.0012 from 1978 uses the famous and reliable, true chronograph movement known as the Lemania 5100, which featured the chronograph (minute hand) counting minutes all around the dial instead of within a small chronograph register. The movement is automatic winding and has a quick-set day/date feature, hour register, constant seconds, and 24-hour indicator at 12:00. We just fully serviced the movement and it is accurate with all functions operating as they should. The steel (original) case is in very good condition for the age of the watch, taking into account the large and thick 42x45x15.6mm case. The original Omega bracelet is very clean with a sea-monster screw back. The dial is in great shape overall, as you can see. These caliber 1045 (Lemania 5100) Omega Speedmasters have become highly sought after lately and we expect to see prices rise, as fewer pieces are seen coming to market.