The AB-01 Tread heavy mecha is a 3 form heavy armed and heavy armored all-purpose and support variable bomber designed to be connected with the Legioss.
It has 3 transformation modes: Armo-Soldier (GiantRobot), Armo-Bomber (Bomber/Heavy Spacecraft) and Armo-Diver (Gerwalk). The Tread can be connected in tandem with the Legioss mecha.
TR.EA.D. stands for "TRans EArth Deployment heavy transformable fighter".