"U.S. soldier wearing a Brewster Body Shield, 1917. The Brewster Body Shield, also and more accurately known as Brewster Body Armor, was the first American body armour to really be useful developed by and for the United States Army in World War I. Essentially, it consisted of a breastplate with an attached headpiece, both able to stop machine gun bullets at an average speed of 820 m/s. The main problems were its heaviness, which was nearly 28 kg. and its discomfort for soldiers. An adapted armour of 5 kg was later created, which fit close to the body, and was considered more comfortable."