AS568-391 O-Ring
Inside diameter 21.955″
Cross-section 0.210″
Outside diameter 22.375″
Metric (ID × CS) 557.66 × 5.33 mm
OD is derived: ID + 2 × CS = 21.955″ + 2 × 0.210″ = 22.375″.
Neighboring sizes (CS 0.210″ series)
| Dash | ID | OD | ID mm | vs -391 |
|---|---|---|---|---|
| -389 | 19.955″ | 20.375″ | 506.86 | ID −2.000″ |
| -390 | 20.955″ | 21.375″ | 532.26 | ID −1.000″ |
| -391 | 21.955″ | 22.375″ | 557.66 | — |
| -392 | 22.940″ | 23.360″ | 582.68 | ID +0.985″ |
| -393 | 23.940″ | 24.360″ | 608.08 | ID +1.985″ |
Same ID, other cross-sections
- AS568-471 — same 21.955″ ID with a 0.275″ cross-section (OD 22.505″)