The Medium Tank M3 was an American tank used during World War II. Design commenced in July 1940, and the first M3s were operational in late 1941. The U.S. Army needed a medium tank armed with a 75mm gun, and coupled with the United Kingdom's demand for 3,650 medium tanks immediately, the Lee began production by late 1940. The design was a compromise meant to produce a tank as soon as possible.
This tag implicates tank (learn more).