The MS-06A Zaku II First Mass Production Type was developed after the MS-05B Zaku I was deemed inadequate for the Principality of Zeon's purposes. Overall, the MS-06A was very much the same as the Zaku I as the Zaku II was merely meant to be an improved version of it. To improve combat abilities, the Zeonic Company increased the armor to give the mobile suit, and thus the pilot, better protection. The thrusters were also improved to give the Zaku II better mobility than the Zaku I. Finally, the Zaku II received improvements to its sensor package and has a more powerful thermonuclear reactor.
To simplify production, the MS-06A used the same armaments of the Zaku I, which consisted of the initial Zaku-type machine gun and a front insertion bazooka. At the time of its deployment the Zaku heat hawk was still in development. Because the Principality's brass did not foresee the Zaku being used in close combat situations, and the fact that the nuclear-weapon using MS-06C was in production, the A-type was never equipped with a heat hawk.