Marxophone
Marxophone is a plucked string instrument or box zither.
Overview
Fretless zither played via a system of metal hammers.
In detail
Marxophone is a plucked string instrument or box zither.
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
“Marxophone”, English Wikipedia, consulted as further reading
Consult the sourcereference work · Reputable secondary · Wikidata
Wikidata, structured authority record Q3296114: Marxophone
Consult the source