Ten-wheel drive, 10WD or 10x10 is a drivetrain configuration of ten 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 lorries. 10x10's are not as common as 4x4's, 6x6's and 8x8's.