Adrian helmet
The Adrian helmet (French: Casque Adrian) is a combat helmet designed by Louis Adrian for the French Army during World War I. Its original version, the M15, was the first standard helmet of the French Army and was designed when millions of French troops were engaged in trench warfare, and head wounds from falling shrapnel generated by indirect fire became a frequent cause of battlefield casualties. Introduced in 1915, it was the first modern steel helmet and it served as the basic helmet of many armies well into the 1930s.