AS568-261 O-Ring

Inside diameter 6.734″
Cross-section 0.139″
Outside diameter 7.012″
Metric (ID × CS) 171.04 × 3.53 mm

OD is derived: ID + 2 × CS = 6.734″ + 2 × 0.139″ = 7.012″.

Neighboring sizes (CS 0.139″ series)

Dash ID OD ID mm vs -261
-259 6.234″ 6.512″ 158.34 ID −0.500″
-260 6.484″ 6.762″ 164.69 ID −0.250″
-261 6.734″ 7.012″ 171.04
-262 6.984″ 7.262″ 177.39 ID +0.250″
-263 7.234″ 7.512″ 183.74 ID +0.500″
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.