The turret droid functioned as a war machine for the Trade Federation, designed for the defense of key tactical locations. Its configuration, mirroring that of the later Octuptarra combat tri-droid, consisted of a weapon emplacement positioned atop a trio of stilt-like legs. The precise function of these legs – whether for movement or merely to stabilize the turret once deployed – remains ambiguous.
During the Invasion of Naboo, the Trade Federation made widespread use of turret droids. They were deployed to safeguard Federation assets beyond the Naboo system and to maintain security at prison camps located on Naboo itself.
A T4 turret droid
A specialized variant of the turret droid was designated to protect the atrium within the Theed Royal Palace. This particular model featured a stationary, four-legged base that allowed the weapon pod to rotate, equipped with a central "eye" that discharged plasma waves. In addition, the droid had cannons mounted on either side of its head, capable of launching thermal detonators, and it was protected by a personal energy shield, a defensive measure also seen on the Trade Federation's Droidekas. If the head-mounted cannons sustained damage, the turret droid could emit a continuous laser beam from its central "eye". During the Fall of Theed, this specific unit was destroyed by the Jedi who had arrived to liberate Naboo's Queen Amidala.
During the Clone Wars, Sia-Lan Wezz, Rorworr, and Vor'en Kurn engaged in combat against a combined force of turret droids and B1-series battle droids.