This helmet started it's life out as a standard German M1918 stahlhelm, and was likely used at the tail end of the first world war. The helmet then saw use under the Reichswehr which was the armed forces of The Weimar Republic. In the early 1930s at somepoint these helmets were sold to The Kingdom of Afghanistan. These helmets saw use with the Kingdom of Afghanistan up until it collapsed in 1973. The two extra holes on the side of the helmet were added by the Afghans for a crest of The Kingdom Of Afghanistan, however after 1973 the new Democratic Republic of Afghanistan inherited these helmets, and removed the old crests which is why there are only two holes remaining. The Democratic Republic of Afghanistan used these helmets up into the Soviet invasion of Afghanistan. The last photos of these in use were seen around circa 1983. After that point we do not really know what these helmets were doing besides laying around. This helmet though was captured by a US Serviceman who was deployed in Afghanistan in the early 2000s. That is how this example made it into the US. These helmets are really neat pieces of history. Only if they could tell us everything they've seen passed through multiple soldiers, armies, and countries.