This is a genuine, rough condition US M1917A1 helmet. Helmet is in untouched condition, exactly as it came to us as part of a large lot of 1917's, 1917A1's, and even some British MkI helmets.
Also known as a the "Kelly Helmet", these were adopted in the years leading up to WW2. They featured a improved suspension over the original 1917 helmets. While some 1917A1's used surplus WW1 production shells, this one features a 1930's production shell made by McCord Radiator.
Condition on this shell is what I would grade as rough. It has rust.
Lot code on the shell is 16C.
No liner nor chinstrap is present on this helmet.
It would be a perfect candidate for restoration or display. Or maybe even making into a lamp?