The Medium Tank M3 was an American medium tank used during World War II. In Britain the tank was called "General Lee", named after Confederate General Robert E. Lee and the modified version built with a new turret was called the "General Grant", named after General Ulysses S. Grant. The M3 was a rapidly produced tank, which filled the void left by the aging interwar M2 tank and was used heavily by British and Canadian forces. The M3 boasted two main guns - a 37 mm in the turret and a 75 mm in a forward sponson of the tank.