T4 Medium Tank
The T4 Medium Tankwas was built at the Rock Island Arsenal in 1935-36 and carried a crew of four. The turret had one .50 caliber and one .30 caliber machine gun, each in separate mounts. The armor was quite thin, ranging from a maximum of 5/8 inch down to 1/4 inch. Its biggest technical achievement was the use of controlled differential steering, which replaced the clutch-brake system used on earlier tanks.