A WW1 brodie helmet converted for an air raid warden in the states. Civilian Defense personnel (especially during the early years or locations that didn't get lots of funding) made do with whatever equipment they could get their hands on.
The helmet is painted white with the warden triangle hand painted on. Also added are D.5,Z.6,C.9, and B.4. I am guessing these were zones that the warden patrolled?
Unfortunately nothing is left on the inside except tape residue.
The helmet also has the markings FS-158, which according to http://www.greatwarcollection.nl/Html/Brodie.html means it was manufactured by Thomas Firth and Sons in Britain from 1915-1919.