AS568-221 O-Ring

Inside diameter 1.421″
Cross-section 0.139″
Outside diameter 1.699″
Metric (ID × CS) 36.09 × 3.53 mm

OD is derived: ID + 2 × CS = 1.421″ + 2 × 0.139″ = 1.699″.

Neighboring sizes (CS 0.139″ series)

Dash ID OD ID mm vs -221
-219 1.296″ 1.574″ 32.92 ID −0.125″
-220 1.359″ 1.637″ 34.52 ID −0.062″
-221 1.421″ 1.699″ 36.09
-222 1.484″ 1.762″ 37.69 ID +0.063″
-223 1.609″ 1.887″ 40.87 ID +0.188″
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.