The M8 "Greyhound" armored car was the only one used in substantial numbers by US forces during WWII. The M20, an offshoot of the M8 design, also played several active roles, in particular serving as a command car for high-ranking officers in forward areas. After WWII, both vehicles, manufactured by the Ford Motor Company served US and various Allied forces around the world. Some countries were still using the vehicles at the turn of the 21st century. The M8 featured an open-top turret in which was mounted an M6 37mm cannon and coaxial Browning .30-caliber machine gun. The M20 replaced the turret with an open-top parapet with a ring-mounted .50-caliber machine gun. When serving as a command car, the M20 packed additional radios and a folding map board.