Italian Firm Oto Melara was a licensed manufacturer of the US M113 and Italy have been a prolific operate of the vehicle, so using it as the base vehicle for a new Anti-Aircraft system saved on the development process and operational costs.
Oto Melara made the necessary modifications to accommodate The Italian SIDAM 25 SPAAG turret, which was built by OTO Breda (a subsidiary of Oto Melara), which the four 25mm Oerlikon KBA (a German manufacturer, which is now part of Rheinmetall Air Defence AG) guns are mounted, the gunner (aiming is via optical sights) and 600 rounds of ammunition.
The Italian SIDAM 25 SPAAG can successively engage low-flying targets at about 2000m (6650ft) firing eight bursts of around two seconds each, at a rate of 2400 rpm. The turret can rotate through 360° and the guns can elevate 87° to -5°. Designated the SIDAM 25, it entered production in 1989 and is only known to be in service with Italy.