These pictures show a Belgian M1 clone used by the Belgian Airforce. The helmet is painted light blue and has a rough texture.
Inside the rim its stamped LS80, I think this means LS = "Linnemann-Schnetzer" a German manufacturer. Still producing sheet metal products.
Or LS stands for Schuberth. 80 is the production year.
I don't know what VPN stands for
Schuberth still makes helmets: https://www.schuberth.com/en/products/military.html
The Liner is brand name = Levoir.