| Nominal Size Inches | Gasket API Number | Number Of Studs | Stud Bolt Size Inches |
|---|---|---|---|
| 2-1/16 | R23 | 8 | 5/8 X 4-1/2 |
| 2-9/16 | R26 | 8 | 3/4 X 5 |
| 3-1/8 | R31 | 8 | 3/4 X 5-1/4 |
| 4-1/16 | R37 | 8 | 7/8 X 6 |
| 5-1/8 | R41 | 8 | 1 X 6-3/4 |
| 7-1/16 | R45 | 12 | 1 X 7 |
| 9 | R49 | 12 | 1-1/8 X 8 |
| 11 | R53 | 16 | 1-1/4 X 8-3/4 |
| 13-5/8 | R57 | 20 | 1-1/4 X 9 |
| 16-3/4 | R65 | 20 | 1-1/2 X 10-1/4 |
| 21-1/4 | R73 | 24 | 1-5/8 X 11-3/4 |
| 26-3/4 | BX167 | 20 | 1-3/4 X 13-3/4 |
