How effective were the 1918 standard-issue infantry helmets of each of the belligerents of WWI? Why did they look so different, country to country? Were the differences primarily aesthetic or functional?

by HuffsGoldStars
HuffsGoldStars

To be clear, I mean how effective was one versus the others (eg. French vs German helmets, etc.)

abt137

I answered a similar question for WWII, you may check here.

https://www.reddit.com/r/AskHistorians/comments/2771tx/in_ww2_which_nations_helmets_were_the_most/