The Mack M123 (G792) was a 10-ton 6x6 semi-tractor introduced in 1955. The Mack M125 was a heavy cargo truck version of the M123. The M123 was used to tow tank transporter trailers while the M125 towed field artillery pieces.

Six-wheel drive is an all-wheel drive drivetrain configuration of three axles with at least two wheels on each axle capable of being driven simultaneously by the vehicle's engine. Unlike four-wheel drive drivetrains, the configuration is largely confined to heavy-duty off-road and military vehicles, such as all-terrain vehicles, armored vehicles, and prime movers.