Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4771476 | Sound chamber closure for an electroacoustic transducer | — | 1988-09-13 |
| 4756308 | Protective breathing mask having a speaking diaphragm for close communication and an electroacoustic transducer system for indirect speech transmission from inside the mask | — | 1988-07-12 |