Kuibyshev Hydroelectric Complex Construction Badge, 1957.
Brass, enamels. Measures 27.4 mm wide, 22.4 mm tall. Scarce variation having screw back attachment rather than pin back (interestingly, the reverse shows a rectangular depression which is a provision for the pin which was never attached). Also features Moscow mint mark "MMD" in horizontal rather than slanted line. Excellent condition. Includes original mint marked screw plate.