The T3-B's ordnance consisted of long-range proton missiles and heavy blaster cannons, making the tank relatively strong against larger targets.
The T3-B was a tracked tank manufactured by Yutrane-Trackata, and was one of the first vehicles fielded by the Rebellion capable of defeating AT-AT walkers in open combat.
Yutrane-Trackata later designed the T4-B heavy tank, an upgraded form of the older T3-B. Though the new T4-B was very powerful and effective during the Galactic Civil War, its implementation did not completely surpass the T3-B, and both tanks were put to great use by the Alliance Army and their other ground forces during the war.
T3-B tanks were later used by the New Republic during the Seizure of Coruscant.
The T3-B heavy attack tank was incorrectly described as a 'heavy hover tank' in Star Wars: Galactic Battlegrounds.