The Hongqi-2 (HQ-2J) is a modified and upgraded Hongqi 2 system, which is itself a modified and upgraded Soviet S-75 Dvina Surface-to-Air missile.
The HQ-2 was the lynchpin of Chinese air security for decades.
The S-75 — called the SA-2 Guideline by NATO — was the missile system that shot down both Francis Gary Powers' and Rudolf Anderson's U2s, as well as John McCain's bomber over Hanoi, Vietnam.