Hearing aid
United States Patent 2787670
US Patent References:
Hearing aid attachment for use on french type telephones
- - 2544027
Spectacle type hearing aid
- - 2613282
Hearing aid attachment for use on french type telephones
- - 2544027
Spectacle type hearing aid
- - 2613282
Inventors:
Rowland, Douglas H.
Publication Date:
04/02/1957
View Patent Images:
Export Citation:
Assignee:
Rowland, Douglas H.
Primary Class:
Other Classes:
381/322, D24/174, 381/328
International Classes:
H04R25/00; H04R25/02