Original M40 helmet marked "Q64" (Quist) with light surface rust but most original paint remaining; there's a large dent in the crown. Norwegian liner is dry but mostly intact with rear seam showing loose thread; marked size 57, no chin strap. 
 
The Quist factory is known for M35 and M40 helmets, especially for the Luftwaffe and only produced only a limited amount of M42 helmets during the war.