AS568-251 O-Ring
Inside diameter 5.109″
Cross-section 0.139″
Outside diameter 5.387″
Metric (ID × CS) 129.77 × 3.53 mm
OD is derived: ID + 2 × CS = 5.109″ + 2 × 0.139″ = 5.387″.
Neighboring sizes (CS 0.139″ series)
| Dash | ID | OD | ID mm | vs -251 |
|---|---|---|---|---|
| -249 | 4.859″ | 5.137″ | 123.42 | ID −0.250″ |
| -250 | 4.984″ | 5.262″ | 126.59 | ID −0.125″ |
| -251 | 5.109″ | 5.387″ | 129.77 | — |
| -252 | 5.234″ | 5.512″ | 132.94 | ID +0.125″ |
| -253 | 5.359″ | 5.637″ | 136.12 | ID +0.250″ |