AS568-249 O-Ring

Inside diameter 4.859″
Cross-section 0.139″
Outside diameter 5.137″
Metric (ID × CS) 123.42 × 3.53 mm

OD is derived: ID + 2 × CS = 4.859″ + 2 × 0.139″ = 5.137″.

Neighboring sizes (CS 0.139″ series)

Dash ID OD ID mm vs -249
-247 4.609″ 4.887″ 117.07 ID −0.250″
-248 4.734″ 5.012″ 120.24 ID −0.125″
-249 4.859″ 5.137″ 123.42
-250 4.984″ 5.262″ 126.59 ID +0.125″
-251 5.109″ 5.387″ 129.77 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.