The RX-78-4 Gundam Unit 4 "G04" is the fourth Gundam mobile suit unit produced during the One Year War. A space oriented version of the RX-78-2 Gundam, Unit 4 possessed a different backpack with more powerful thrusters and the mighty Mega Beam Launcher - a colossal, massively destructive weapon that required the suit's total output to be fired, which rendered it completely immobile during firing.