Berezin UB
Berezin UB is an aircraft machine gun or artillery model.
Also recorded as UB; UBS; UBT; UBK; BS.
Overview
12.7 mm machine gun aircraft armament.
In detail
It is associated with Soviet Union. The record gives 1938 as its date of establishment or first appearance.
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
“Berezin UB”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q819089: Berezin UB
Consult the source