What you have there is British or Aussie both helmets nearly look the same, sorry i couldent tell you witch one it is...
This looks like an American civil defense helmet to me
Ok! i see now! I guess it's an early ww2 civil helmet from the US, I couldn't recognise the liner though but the chinstrap matches other ones. Thanks!
Australian made examples do not have the rolled lip around the rim.
This is a American civil defense helmet https://www.google.com.au/search?hl=...mg.EkcIHXa0FY0
This is an Aussie one https://www.google.com.au/search?hl=...w=1152&bih=702
That's not American. I have an early Brodie style Civil Defense helmet and the liner looks nothing like that. I once seen one on e-bay but the seller didn't even know where it's from. It could be construction or a miners helmet, or a prop type used for movies?