German steel helmet M 31 liner made by Schuberth Werk KG Braunschweig 1940

German steel helmet M 31 liner made by Schuberth Werk KG Braunschweig in 1940 year. Size 66 /58 marked. Worn condition , small period repair, leather has some darking ends, but still soft. Fit to M 16/M18/M35/M40 helmets