M 1958 Air Force Engineering Service Officer badge, Non-Rated, 1959 - 1980s.
The badge was among the four new qualification badges for the Air Force flight engineers and officers of ground technical services established in 1958. Starting from the following year, the non-rated badges were made in aluminum rather than brass as a cost-cutting measure.
/Kibovskiy et al, Uniforms of Russian Air Force, Vol. II (Part 2) , 2005 edition, pp. 93-94/.