Socimi Type 821
Socimi Type 821 is a submachine gun or weapon model.
Also recorded as Milano 821.
In detail
It is associated with Italy.
Sources
Each source is named with the standing the house places on it, so the evidence can be weighed rather than taken on trust.
reference work · Reputable secondary · Wikipedia
“Socimi Type 821”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q7552753: Socimi Type 821
Consult the source