A self-propelled anti-aircraft weapon (SPAA, also self-propelled air defense, SPAD, or self-propelled anti-aircraft gun, SPAAG) is an anti-aircraft gun or surface-to-air missile launcher mounted on a mobile vehicle chassis. The Russian equivalent of SPAAG is ZSU, for zenitnaya samokhodnaya ustanovka, ("anti-aircraft self-propelled mount").
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