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AS568-344 O-Ring Size
300 series · 3/16" cross section · Heavy hydraulics, higher pressure
Inside diameter × cross section
97.79 × 5.33 mm
3.85″ × 0.21″ ·
outside diameter 108.46 mm (4.27″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 3.85″ | 97.79 mm |
| Cross section (CS) | 0.21″ | 5.33 mm |
| Outside diameter (OD) | 4.27″ | 108.46 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 97.79 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -344 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) |
|---|---|---|---|
| -343 | 94.61 | 3.725″ | 105.28 |
| -345 | 100.97 | 3.975″ | 111.63 |
| -346 | 104.14 | 4.1″ | 114.81 |
| -342 | 91.44 | 3.6″ | 102.11 |