The S-25 Berkut (; "Berkut" means golden eagle in English) is a surface-to-air guided missile, the first operational SAM system in the Soviet Union. Its NATO reporting name is SA-1 Guild. It was used only to defend Moscow, while the more mobile S-75 (SA-2 Guideline) would be used in almost all other roles. Other names include the R-113 (target acquisition radar), B-200 (target engagement radar), A-11/A-12 (antennas for B-200), and V-300 (a SAM); S-25 is for Systema 25, referring to the system as a whole.