I believe it's a Luftschutz helmet that someone's been gimmiking around with.
The shell is a typical beaded m.40
The liner is typical for a Luftschutz.
The finger holes do not have reenforcing leather grommets.
The spacers are cork, again, typical for a Luftschutz liner.
As are the oilcloth inner band...
the felt cushion...
and the cardboard mounting band.
In true m.40 fashion the edge is rolled...
and the ventilator is stamped. Don't get excited by the remnants of the decal, it was a cheap replica water-slide applied by the dealer.
Under the green pain is a grayer layer.
The overpainting was done with a brush.
The number in the skirt is 220...
the size is 66 and the manufacturer is Eisenhuttenwerke, Thale.
Now here's the fishy part...
The chinstrap appears to be from a Polish wz.67.
And there are very suspect markings ink stamped on the liner fingers.
Guesses, anyone?
Don't ask me, I'm stumped.