This is a favorite prop of mine.
It took me forever to find the correct model for my conversion.
Like many props they happened to get the rarest version of this helmet.
It is an AN-H-15 Summer Flying Helmet as stated above BUT most of these helmets have leather reenforcement pieces added where the snaps are to prevent tearing when unbuckling the oxygen mask from it. The one used is an earlier verision that doesn't have these leather pieces. Another difficult variation is the number and arrangement of the snaps. You'll find every number and combination under the sun. These "No Leather" helmets also go for more on Ebay since they are earlier specimens and are prone to tearing. Finding a size you can wear is also difficult since everyone had tiny heads back then. Frustrating to say the least.
Also you can see in this pic that a snap-on oxygen mask hook is attached to two of the snaps and then covered in greeblies.
The head set is a strange attachment historically.
Most of these helmets use radio ear pieces similar to this-
What is used on the helmet is a mangled version of this stand alone headset-
There are a couple minor variations in the head set design and the Gaff used one has a line of little holes in the metal piece on the ear cup. Many versions do not.
The one mystery in this set-up for me is the metal piece attached to the ear cup. It sorta resembles the boom mic attached found on some of these helmets but not exactly. I've searched around to find some sort of variant that matches without luck.
The little clear tubes are called voice tubes and be found on ebay pretty cheap. It actually took a bit of searching to figure out the proper name to search for.
I still haven't found a good ribbed wire that is found on top of the headset.
I think that covers most of the stuff I've figured out so far.
If anyone wants to grabs some caps from the newer BR DVD of this helmet it would be much apreciated.
Nick