
The Ardente Hearing aid, London, England, 1920-1930
1920-1930
1920-1930
1990-96
1960
circa 1945
1931
1930
1830 (original); 1967 (model)
circa 1955
circa 1956
1959
circa 1960
circa 1950
circa 1950
1950-1960
1955
1949
1947
circa 1920
1950
1921-1940
1947
1922
1924
1958-1960
1923
1920-1930
1930-1962
1914-1918
1950
1920-1950
1959
1908-1950
1948
1926
c.1912
c.1912
1930-1939
1939
1955
circa 1956
1948
1910-1937
1953
1938
1935
1937
1938
1930 (replica); 1834 (original)
1958
1919