The ZSU-23 or ZU-23-2 is a dual mounted 23mm calibre autocannon anti aircraft gun. The large calibre rounds can inflict an incredible amount of damage against aricraft, light armour and infantry (especially when high explosive incendiary rounds are used...)
These are frequently seen mounted in Technicals accross the Middle East and Africa. The extreme recoil when fired can cause problems if the truck isn't positioned correctly!
The ZSU-23 is a complete kit including crew and base plate, allowing it to be mounted on Technical Alfa and Technical Bravo, with some modification to the base plate legs.