AS568-253 O-Ring

Inside diameter 5.359″
Cross-section 0.139″
Outside diameter 5.637″
Metric (ID × CS) 136.12 × 3.53 mm

OD is derived: ID + 2 × CS = 5.359″ + 2 × 0.139″ = 5.637″.

Neighboring sizes (CS 0.139″ series)

Dash ID OD ID mm vs -253
-251 5.109″ 5.387″ 129.77 ID −0.250″
-252 5.234″ 5.512″ 132.94 ID −0.125″
-253 5.359″ 5.637″ 136.12
-254 5.484″ 5.762″ 139.29 ID +0.125″
-255 5.609″ 5.887″ 142.47 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.