American military technology during World War II US cruisers and battleships had their guns directed using information gathered from the ship's radar. American military technology during World War II American military technologies developed during World War II became more advanced and specialized as the war progressed. The technologies produced ranged in complexity from relatively simple items such as small arms and armored vehicles, including tanks, to more complex items such as the atomic bomb. The latter, produced under the secretive Manhattan Project, proved to be an incredibly powerful weapon that revolutionized warfare and was used to end the war. Other technologies, such as the M4 Sherman tank,
Main battle tank roles, such as "cavalry tanks", "breakthrough tanks", "fast tanks", and "assault tanks". The British maintained cruiser tanks that focused on speed, and infantry tanks that traded speed for more armour. After years of isolated and divergent development, the various interwar tank concepts were finally tested with the start of World War II. In the chaos of blitzkrieg, tanks designed for a single role often found themselves forced into battlefield situations they were ill-suited for. During the war, limited-role tank designs tended to be replaced by more general-purpose designs, enabled by improving tank technology. Tank classes became mostly based on weight