In looking at the design of the watches Omega was developing in the early 1970s, it is apparent that the Seamaster reference 176.004 "Big Blue" (named for the obvious reasons that it is both large and blue) took architectural cues from several references that were also being introduced in the late 1960s and early 1970s that echoed the futuristic ethos typical of the era such as orange hand of the so-called “PloProf” and the prototype Seamaster 1000 and the oversized tonneau-shaped case of the Flightmaster. It is, however, most similar to the reference 176.002 Speedmaster "Mark III", first introduced in 1971. The case is mountainous, summited by a uni-directional rotating bezel, with vertical brushed finishing throughout.

Ref Variations: ST176004,