The B2 super battle droid (SBD) was an upgraded version of the B1 battle droid, with superior armament and armor. They were manufactured after the battle on Skylar Green proved need for stronger droids. B2s were used by the Axis of Empires (Mostly the Separatists). Some units were later reactivated on Mustafar by Gizor Dellso and other members of the Separatist holdouts, and the Coalition of Independent States also used some B2 units during the Chaos War.
One of the main design flaws of the standard B1 battle droid was its reliance on a Droid Control Ship to provide a signal; if the ships were disabled, the battle droids would become useless. To remedy this, the super battle droid did not rely on such a signal and had a greater capacity for independence. However, the droid still operated best with a command signal, otherwise they tended to forget about enemies as soon as they moved out of visual range. Additionally, the sturdy duranium frame of the super battle droid was larger and more heavily armored than those of a B1.