The 50R6 Vityaz or S-350E is a Russian medium-range surface-to-air missile system developed by GSKB Almaz-Antey. Its purpose is to replace the S-300PS and S-300PT-1A. The system design traces its roots from the joint South Korean/Russian KM-SAM project and uses the same 9M96 missile as the S-400 missile system.