It consisted of two pressed steel plates that protected the front torso and groin. The plates were 2 mm and weighed 3.5 kg. This armor was supplied to SHISBr (assault engineers) and Tankodesantnikam (infantry that rode on tanks) of some tank brigades. Real combat experience showed that the MP-40 9 mm bullet failed to penetrate at around 100-125 m. It was very useful in dense, intense urban battles (Stalingrad) where the Germans used the MP-40 predominantly, but, because of its weight, was not practical for soldiers charging across an open field.

Military equipment of the Soviet Union | Personal armor