The ZSU-57-2 (Ob'yekt 500) is a Soviet self-propelled anti-aircraft gun armed with two 57 mm autocannons. ZSU stands for Zenitnaya Samokhodnaya Ustanovka (Russian: Зенитная Самоходная Установка), meaning "anti-aircraft self-propelled mount", 57 stands for the bore of the armament and 2 stands for the number of gun barrels. It was the first Soviet mass produced tracked SPAAG. In the USSR it had the unofficial nickname "Sparka", meaning "pair", referring to the twin autocannon with which the vehicle is armed.
Basing on past experiences with SPAAG designs, Soviet engineers designed a vehicle that used a modified T-54 chassis, with four twin road wheels per side instead of five, and with much thinner armour. The vehicle was armed with the 57 mm S-68 twin AA autocannon in a new large rotatory open-topped turret. The ZSU-57-2 consists of three compartments: driver's in the front, fighting in the middle and engine-transmission in the rear. The hull of the ZSU-57-2 is more spacious in comparison with the T-54 medium tank because of the thinner armour and has different location of some equipment also. The general layout with transverse mounting of engine is the same.
