# The US armored helmet has changed greatly over the years. In the First World War, the M1917 / M1917A1 helmets used by US troops were known as "Dabway" or "Dispun", which protected the soldiers' head. During the Second World War in 1941, the helmet was replaced by the M-1 "steel pot" helmet. In the 1980s US Helicopter Helmet was further improved by the Kevlar 29 missile fiber. The helmet used in the future may have more protection and convenience.
Currently a group of Arizona State University researchers is trying to create a helmet for US military under the US Defense Advanced Research Projects Agency, which will be able to control the minds of the soldiers through sound waves. It will have many effects on the battlefield. Using a controller, the army can stimulate some parts of the brain by stimulating ultra sound pulse timely. Besides, they can also use it for release of stress, and may even be able to forget pain, which does not have to use anti-drug medicines.