A very good, and apparently unissued example of the Royal Air Force Type C Flying helmet.
This example with impressed RAF 22C stores number to the lower left hand side exterior, and ink stamps to either side of the interior.
No staining or marks to the interior chamois leather. Polystyrene has been placed in in rubber recievers which has kept them in excellent shape.
Good elastiscity remaining to the chin strap.
The only flaw I can see, and it is rather minor, are some small flecks of white emulsion paint to the exterior, which should be easy enough to vanquish.