This 40 kopeck red-brown Soviet stamp was issued in 1940 to commemorate the All-Union Industrial Exhibition, a showcase of the USSR’s technological progress. The design features the massive turbine wheel of the Kuybyshev Hydroelectric Station (Kuibyshev GES), a symbol of Soviet industrial might and engineering achievement. Workers are seen examining the turbine, emphasizing collective labor and innovation. The stamp reflects the industrial optimism of the pre-war Soviet era and is part of a broader series celebrating national industry.