T3's modular design made it simple to equip him with an array of blasters, disrupters, flamethrowers, scramblers, shock arms and different sets of droid armor with little hassle. These weapons complimented his impressive array of tools that could be used to repair items, open locked doors and perform other tasks that would be almost impossible for an organic being.
T3-M4 (also called Teethree for short) was a T3 series utility droid designed for crime lord Davik Kang to be a master slicer. Before Davik could acquire him he fell into the service of an amnesiac Revan, the quirky little droid accompany Revan throughout his quest for the Star Forge. When Revan left for the Unknown Regions after defeating Darth Malak he left T3 behind with his ship, the Ebon Hawk which was used to rescue the Jedi Exile from Darth Sion, a member of the Sith Triumvirate.