These are unused and unissued M1 helmet liners.
All of these are from the 1980's, and feature the later issue clip in suspensions.
None of them include sweatbands nor nape strapes.
Nomenclature: Liner, Helmet
Ground Troops
Type I
NSN: 8470-00-935-6843
Almost all have 1983 contract dates on them.
Liner may have very small scuffs on the outside from long term storage, but they are all unused.