This is a German WWII RLB Reichsluftschutz gladiator helmet (Air Raid Protection helmet).
Kopfweite 57, which is a nice size.
In very good condition with most of it’s dark blue color present and only minor age damage. The decal on the front is in good condition too.
Complete with liner and chin strap (although im not sure if that is original to the helmet because of the closing device that seems modern to me?).