World War 1 period helmet used by the US Army. Shell painted in matte green khaki paint. Painted on the side with a red symbol - the mark of the 28th American "Iron" Infantry Division, originally the mark was on the front of the helmet, after which it was moved to the side. Interior with the original bolster and sweatbox. Good condition as shown in photos.
https://en.wikipedia.org/wiki/28th_Infantry_Division_(United_States)
