Japanese M18 helmets were first introduced initially by the Japanese during their conquest of Manchuria region in the Sino Japanese conflicts. I had a type 90 Japanese helmet created by Setwarts Military Antique and it covered exactly the circumference of my existing original Japanese type 90 so I imagine this M18 reproduction should be reasonably accurate if not identical to the real thing. Oirignal Japanese M18 helmets if found cost starting at $1500 us up for just a rusty shell so you are really looking at a very rare helmet even for reproduction version. I included 2 photos from Japanese magazine of the real M18 in action in Shanghai against Chinese people. Don't ask me why I collect Japanese helmets. Ask some of my helmet collector friends who are Jewish why they also collect German helmets.