AS568-316 O-Ring

Inside diameter 0.850″
Cross-section 0.210″
Outside diameter 1.270″
Metric (ID × CS) 21.59 × 5.33 mm

OD is derived: ID + 2 × CS = 0.850″ + 2 × 0.210″ = 1.270″.

Neighboring sizes (CS 0.210″ series)

Dash ID OD ID mm vs -316
-314 0.725″ 1.145″ 18.41 ID −0.125″
-315 0.787″ 1.207″ 19.99 ID −0.063″
-316 0.850″ 1.270″ 21.59
-317 0.912″ 1.332″ 23.16 ID +0.062″
-318 0.975″ 1.395″ 24.76 ID +0.125″
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.