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AS568-443 O-Ring Size
400 series · 1/4" cross section · Industrial flanges and piping
Inside diameter × cross section
189.86 × 6.99 mm
7.475″ × 0.275″ ·
outside diameter 203.84 mm (8.025″)
Dimensions
| Dimension | Inches | Millimetres |
|---|---|---|
| Inside diameter (ID) | 7.475″ | 189.86 mm |
| Cross section (CS) | 0.275″ | 6.99 mm |
| Outside diameter (OD) | 8.025″ | 203.84 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 189.86 mm, because compression set is permanent. If your measurement came in a little under this and the cross section roughly matches, -443 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 400 series
These share the same 1/4" 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) |
|---|---|---|---|
| -442 | 183.51 | 7.225″ | 197.48 |
| -444 | 196.21 | 7.725″ | 210.19 |
| -441 | 177.16 | 6.975″ | 191.13 |
| -445 | 202.56 | 7.975″ | 216.53 |