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AS568-245 O-Ring Size
200 series · 1/8" cross section · General purpose, cylinders
Inside diameter × cross section
110.72 × 3.53 mm
4.359″ × 0.139″ ·
outside diameter 117.78 mm (4.637″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 4.359″ | 110.72 mm |
| Cross section (CS) | 0.139″ | 3.53 mm |
| Outside diameter (OD) | 4.637″ | 117.78 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 110.72 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -245 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) |
|---|---|---|---|
| -244 | 107.54 | 4.234″ | 114.6 |
| -246 | 113.89 | 4.484″ | 120.95 |
| -243 | 104.37 | 4.109″ | 111.43 |
| -247 | 117.07 | 4.609″ | 124.13 |