AS568-340 O-Ring

Inside diameter 3.350″
Cross-section 0.210″
Outside diameter 3.770″
Metric (ID × CS) 85.09 × 5.33 mm

OD is derived: ID + 2 × CS = 3.350″ + 2 × 0.210″ = 3.770″.

Neighboring sizes (CS 0.210″ series)

Dash ID OD ID mm vs -340
-338 3.100″ 3.520″ 78.74 ID −0.250″
-339 3.225″ 3.645″ 81.91 ID −0.125″
-340 3.350″ 3.770″ 85.09
-341 3.475″ 3.895″ 88.27 ID +0.125″
-342 3.600″ 4.020″ 91.44 ID +0.250″
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.