The T4 turret droid, originating from the Colicoid Creation Nest, was a sizable, multi-limbed battle droid.
These droids were initially constructed a number of years prior to the Invasion of Naboo. Their main purpose was to serve as a movable defensive structure, providing security for important figures when they traveled to dangerous planets. During the invasion event, a significant number of these droids were reassigned to Theed with the goal of maintaining order and stopping the queen from escaping. Despite not succeeding in preventing her departure, their overall performance was sufficient for them to remain in service until the early period of the Clone Wars. A new unit had a price tag of 26940 credits and their use was limited to military applications.
T4 droids mainly operated in defensive roles, frequently positioned in areas such as intersections or security checkpoints. They had the capability to be adapted for various roles including artillery observers, surveillance outposts, or patrolling sentry droids.