Production for the M2 Medium Tanks was 18 M2 tanks, and 94 M2A1 tanks, for a total of 112. For combat it was a poor design, with thin armor, inadequate main armament and a high profile. The four sponson-mounted machine guns proved to be completely unnecessary. But it provided important lessons that were used for the later M3 and M4 medium tanks. In particular, the M2's sloped frontal hull armor (glacis plate) was extremely advanced for a 1939 design, and would become a permanent feature of U.S. tank design. Events in Western Europe and on the Eastern Front rapidly demonstrated that the M2 was obsolete, and it was never used overseas in combat; it was used for training purposes throughout the war.
