the Red Army , called SN-38, SN-39, SN-40, SN-40A, and SN-42 (The native Cyrillic abbreviation for the vest was СН, the Cyrillic letters Es and En .) "Stalynoi Nagrudnik" is Russian for "steel breastplate", and the number denotes the design year. All were combat tested, but only the SN-42 was put