Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5819745 | Pressure-regulating ear plug | Chaoying Zhang, Sigfrid D. Soli, Chris D. Johnson, Drew O'Connell | 1998-10-13 |
| 5755234 | Pressure-regulating ear plug | Chaoying Zhang, Sigfrid D. Soli, Chris D. Johnson, Drew O'Connell | 1998-05-26 |
| 5467784 | Pressure-regulating ear plug | Chaoying Zhang, Sigfried D. Soli, Chris D. Johnson, Drew O'Connell | 1995-11-21 |