Twelve-wheel drive, 12WD or 12x12 is a drivetrain configuration of twelve wheels, all of which are driven simultaneously by the engine. Unlike four-wheel drive drivetrains, this configuration is only used in extreme off-road and military uses, in particular heavy duty uses, such a heavy haulage and missile carriers. It is also used in trucks. Tatra T816 12x12 is example of vehicle using this particular driveline system. In this configuration both two front axles and both two rear axles of T816 are steerable. It is used e.g. as Brahmos supersonic cruise missile carrier.