Protective Face Mask, United Kingdom, 1917-1918

Masks like this one were worn by British crews in tanks during the First World War. The leather mask is shaped to fit around the eyes and nose and the chain mail was used to protect against splinters from explosions as the tank came under fire. 

Life inside these primitive vehicles would have been extremely uncomfortable as well as dangerous. Tanks were introduced in 1916 but were initially slow, difficult to manoeuvre and had little firepower. (Source)