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AS568-906 O-Ring Size
900 series · mixed cross section · SAE straight-thread boss gaskets
Inside diameter × cross section
11.89 × 1.98 mm
0.468″ × 0.078″ ·
outside diameter 15.85 mm (0.624″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 0.468″ | 11.89 mm |
| Cross section (CS) | 0.078″ | 1.98 mm |
| Outside diameter (OD) | 0.624″ | 15.85 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 11.89 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -906 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 900 series
These share the same mixed 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) |
|---|---|---|---|
| -905 | 10.52 | 0.414″ | 14.17 |
| -907 | 13.46 | 0.53″ | 17.63 |
| -904 | 8.92 | 0.351″ | 12.57 |
| -903 | 7.65 | 0.301″ | 10.9 |