Produced between 1955 and 1963, the P55 M1 Helmet Liner was the first version not to have a front insignia eyelet.1 Made from laminated cotton duck, the liner featured:
An improved suspension system for the M1 Helmet Liner was introduced in 1964.
- suspension webbing that could be adjusted to hold the liner at the right height on the wearer's head
- neck strap and adjustable neck band that was designed to prevent the helmet from pitching forward
- leather lined headband that could be adjusted to the wearer's head size
- leather chin strap
1. Reynosa, Post-World War II M-1 Helmets, pp 34