Assertion: derby mute | /r/HasProperty | stamped by elton
Facets:
value: in the 1920s
type: TEMPORAL
value: out of metal
type: OTHER
Source sentences:
text: In the 1920s, with the advent of aluminum as an art metal, derby mutes were stamped out of metal by companies such as Meta-Lite, Elton, and later Harmon.