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AS568-357 O-Ring Size
300 series · 3/16" cross section · Heavy hydraulics, higher pressure
Inside diameter × cross section
139.06 × 5.33 mm
5.475″ × 0.21″ ·
outside diameter 149.73 mm (5.895″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 5.475″ | 139.06 mm |
| Cross section (CS) | 0.21″ | 5.33 mm |
| Outside diameter (OD) | 5.895″ | 149.73 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 139.06 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -357 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 300 series
These share the same 3/16" 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) |
|---|---|---|---|
| -356 | 135.89 | 5.35″ | 146.56 |
| -358 | 142.24 | 5.6″ | 152.91 |
| -355 | 132.71 | 5.225″ | 143.38 |
| -359 | 145.41 | 5.725″ | 156.08 |