ZSU-57-2
The ZSU 57-2 was the first successful post-WW2 SPAAG (self-propelled anti-air gun) designed by the Soviet Union, meant to provide air cover for the Soviet tank brigades from capitalist jets of the 50s and 60s. Nicknamed the 'Sparka' (pair) by the Soviet Union, the vehicle is essentially a T-54 chassis with a pair of 57mm autocannons designed to knock slow flying planes out of the skies, and firing at ground targets with very deadly force.
In Team Yankee
Disclaimer: the following is based on 'Fate of a Nation'. Clarifications and more details will be provided with the release of 'Oil Wars'!
The ZSU-57-2 functions as the anti-armour older brother to the Shilka, trading Radar for additional ground range up to 24", AT9, FP 4+ and a ROF of 3/2. Uniquely in Team Yankee, this is one of the only anti-air units whose threat bubble is only good enough for surrounding units and not three-quarters of the table. Unable to touch helicopters, its guns are only usable against enemy bombers dropping their load right over your head.
Unlike the Shilka, the ZSU-57-2 has some very deadly weapons when targetting ground vehicles. It automatically penetrates anything with a front armour of two, and IFVs like the Marder will have to roll 5 or better to avoid bailing or burning up. FP4+ may not be the most reliable, but outperforms all autocannons from the M247 Sergeant York. In terms of raw firepower, the ZSU is deadlier than the SA-13 Gremlin with an additional shot but it lacks the range of its counterpart. Fortunately, using the two of these AA units gives you a very respectable air-cover umbrella with the Gremlins shooting whatever the ZSUs cannot.
The ZSU boasts a front armour of two, sides of one but top armour 0. However, the low range of its 57mm guns means that you should be attacking with this unit as much as possible. Employed as a light tank, it comfortably keeps pace with a company of T-72Ms while providing a respectable level of air cover against aircraft, but leaves them totally vulnerable to NATO choppers.