AS568-381 O-Ring

Inside diameter 11.975″
Cross-section 0.210″
Outside diameter 12.395″
Metric (ID × CS) 304.16 × 5.33 mm

OD is derived: ID + 2 × CS = 11.975″ + 2 × 0.210″ = 12.395″.

Neighboring sizes (CS 0.210″ series)

Dash ID OD ID mm vs -381
-379 10.975″ 11.395″ 278.76 ID −1.000″
-380 11.475″ 11.895″ 291.46 ID −0.500″
-381 11.975″ 12.395″ 304.16
-382 12.975″ 13.395″ 329.56 ID +1.000″
-383 13.975″ 14.395″ 354.96 ID +2.000″

Same ID, other cross-sections

Data provenance. SAE AS568, Aerospace Size Standard for O-rings (SAE International). Nominal dimensions per AS568; size tolerances vary by dash number and are not yet cataloged. Groove/gland design depends on the application — consult a gland design reference. See all data sources.