Nice old microphone complete with original bakelite stand. Good condition as shown but I havn't tried it. Google info that I found is: Acos MIC 22 crystal microphone, 1951. Crystal (or piezo) microphones had a high signal output, but rather indifferent quality. They were often used with reporter's tape recorders. Speech only, public address, recording, amateur radio. The price for this microphone in 1951 was £6-6-0.