It looks to me operated by steam created by the back of the neck.
Because of that it can operated in hot climates only
Making it that much more rarer.
A good find although the visor trim and cocardes may be questionable as others have said.
Sorry Brian, I would be happy to, but the guy selling it says it is a size 52 and I'm a 60 (not bragging of course).
PS. If you really have to see what I look like just look at my avatar. That's Ludwig III but he's a dead ringer for me- that's why I picked it!