The M3 Lee medium tank was the main U.S. counter to the formidable tank forces available to the German army in the early stages of WWII. Before the M3 Lee was developed, the U.S. forces only had light tanks at their disposal as the 37mm gun M2 was already practically obsolete by the time it was ready for mass production. Given time constrictions, the solution chosen was to attach a 75mm gun to the M2's hull and attach the 37mm gun to a swiveling turret; 7.62mm machine guns were added to a further turret to give the new tank a distinctive 3-level form. It was named the M3. Despite problems such as limited rotation of the 75mm gun and the height of the tank making it rather easy to spot, its powerful weaponry and strong armor made it a highly useful stop gap for the Allied forces. It was also used by the British, who gave it the naming 'Lee' (or 'Grant' for versions with a different turret pattern). With the advent of the M4 Sherman, the M3 Lee saw more action in the Pacific Theater, tussling with Japanese forces until the end of the war.