S-75 Dwina Missile in the Vietnam War

Soviet-Designed, High-Altitude Air Defence System

The S-75 is a Soviet-designed, high-altitude Air Defence System, built around a surface-to-air missile with command guidance. Since its first deployment in 1957 it became one of the most widely deployed air defence systems in history. Wikipedia
Guidance system: Radio control command guidance
Operational range: 45 km (28 mi)
Flight altitude: 25,000 m (82,000 ft)
Warhead weight: 200 kg (440 lb)
Warhead: Frag-HE
Speed: Mach 3.5