He meant England proper, over the pond.
also note date on bottom of the advertisement, a great clue . Many air raids in the UK during WW2, perhaps the inspiration for protecting the states the same way.
Harry was an Italian immigrant who came to New York City. Later retired to Phnx where he went back into production for a short while. He also made the sirens himself, foundry, no production lines or big industrial company.
Owner of: (Don't ask me why)
A Small demolition 110v siren,
Federal model A 110v,
Federal type 2 240v,
Federal 2001 DC roundback,
and a Harry O. Ricci Model 50 Super Si-Rex 10/10 port Dual Horn 3 phase.