United States Patent 3233041
US Patent References:
/1658327.html
- - 1658327

/2159533.html
- - 2159533

/2169806.html
- - 2169806

/2614646.html
- - 2614646

/2755336.html
- - 2755336


View Patent Images:
Primary Class:
Other Classes:
381/109, D24/134, 600/586
US Patent References:
2820107Electro-mechanical signal transducers
2848560Hearing aid receiver
3087016Stethoscopic device