R2-D2 is a tripodal computer repair and information retrieval robot, or astromech droid. As an R2 unit, he is equipped with navigational starfighter interfaces, plus extensive sensor packages and numerous devices to facilitate in-flight repairs: laser arc welder, circular saw, grasper arm, and fire extinguisher. He communicates through information-dense chips, beeps and whistles and seems to take pleasure in causing anxiety for his neurotic companion, the protocol droid C-3PO.