Issued Patents 1997
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5657527 | Methods for making light-weight drainage line units | Michael Houck, Harold J. Houck | 1997-08-19 |
| 5639364 | Light-weight drainage line units | Michael Houck, Harold J. Houck | 1997-06-17 |