Tank Droid
a combat droid programmed with artificial intelligence, tank droids have been used by many different factions throughout galactic history. The first full-scale use of these droids was by the Corporate Alliance of the Old Republic, during the years leading up to the Clone Wars. The Corporate Alliance actually employed a wide variety of combat droids to protect their interests. The Corporate Alliance's NR-N99 tank droids were large, circular automatons with a huge central wheel supported by four small outrigger wheels. This droid could roll into and out of battle with ease, and was equipped with a variety of weapons systems mounted on arms. Years later, the Empire used other forms of tank droids to protect the cloning facilities on Byss, following the Battle of Endor.