Portuguese M40 helmet shells. These are incomplete, and will need liners, and most will need chin straps. These are genuine surplus, and are extremely hard to find. Simply install a U.S M1 style webbing into the shell, and use an M1 Chin Strap, and you have a Portuguese M40/63 helmet for your collection.
You will not find these anywhere, and once these are gone, they're gone.
Expect Shells to have broken liner band hooks and have the chinstrap missing.
Sold as a collectible/restoration item.