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AS568-281 O-Ring Size
200 series · 1/8" cross section · General purpose, cylinders
Inside diameter × cross section
380.59 × 3.53 mm
14.984″ × 0.139″ ·
outside diameter 387.65 mm (15.262″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 14.984″ | 380.59 mm |
| Cross section (CS) | 0.139″ | 3.53 mm |
| Outside diameter (OD) | 15.262″ | 387.65 mm |
Outside diameter is not measured, it is derived: OD = ID + 2 × CS.
If your measured OD disagrees with this, trust the ID and cross section — measuring
across the outside of a flexible ring is the least reliable of the three.
If you measured a used one
A ring pulled out of service will measure smaller than 380.59 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -281 is very likely still the correct part. Ordering the size your worn ring measures is how the same failure repeats. More on this →
Nearby sizes in the 200 series
These share the same 1/8" cross section, so if the thickness is right but the diameter is off, your ring is probably one of these.
| Dash | ID (mm) | ID (in) | OD (mm) |
|---|---|---|---|
| -280 | 355.19 | 13.984″ | 362.25 |
| -282 | 405.99 | 15.984″ | 413.05 |
| -279 | 329.79 | 12.984″ | 336.85 |
| -283 | 431.39 | 16.984″ | 438.45 |