S-400 missile system

The S-400 Triumf, previously known as the S-300 PMU-3, is a mobile, surface-to-air missile (SAM) system developed in the 1990s by Russia's Almaz Central Design Bureau for Marine Engineering as an upgrade to the S-300 family. The evolved version of the S-400 system is the S-500 Prometheus, which entered service on 16 September 2021.