7,7 / 10


Very rare model

Perfect condition

Service dial






This watch is an extremely rare example of Seamaster 120 “Big Blue”.

Due to its low production and intensive use at a time when people actually wore their watches on their job (on dives in this case), finding a “Big Blue” today in such an amazing condition is extremely difficult.

Please note that the dial is not the original one. It is a service dial, which has been relumed with tritium.

This feature has an impact on the watch score.

About the model

Omega perhaps understood better than any other company the essence of a diver watch. From the first Seamaster 300 (CK 2913) up to the Seamaster 600 Ploprof (ST 166.0077) and the Seamaster 1000 (ST 166.0093) for instance, the company tried to improve the whole idea of the diver tool watch by experimenting with new materials or bold technical approaches in order to solve issues the watches faced in extreme environments.

The Seamaster 120 ST 176.004, or “Big Blue”, represents all the lessons that the company had learned up to that point.

The engineers at Omega had the idea to overcome the combination of the three hand/bezel offerings and produce a chronograph with a big central minute hand. For that they needed first and foremost a caliber that could support this configuration and could be robust enough and highly accurate: their obvious choice was the caliber 1040. Omega first introduced this same caliber in two Seamaster chronographs (ST 176.001 and ST 176.007), in the Speedmaster MkIII (ST 176.002) in 1971/1072, and with a certified chronometer version in the famous Speedmaster 125 in 1973 (caliber 1041, ST 378.0801).

So the Seamaster “Big Blue” had an extraordinary movement that had all the ingredients needed to power a proper tool diver chronograph. Another characteristic that made the watch stand out from the crowd was its size and, most notably, its shape. Its helmet-shaped case is distinctive. The company first introduced these cases in 1969 in their Flightmaster model and continued the trend with the Speedmaster MkIII.

The dial of the watch and its bezel are also highly characteristic. The blue color is specific and changes tint depending on the angle you look at it from. The configuration is classic for a 1040 caliber.