Qualitone audiometer with instruction manual, made by the Qualitone Company, Minneapolis, U.S.A., 1960-1965. Qualitone audiometer with instruction manual 1960-1965
Audiometer, for measuring hearing ability, by Amplivox, London, England, c.1965 Audiometer, by Amplivox, London, England, c. 1965 1965
Audiometer for testing hearing, in wooden case, by Amplivox Ltd., London, 1951-1960. Audiometer for testing hearing 1951-1960
Politzer's acoumeter, steel with bone frame, by, Heinrich Reinder Vienna, 1875-1910 Politzer's acoumeter 1875-1910