AS568-155 O-Ring

Inside diameter 3.987″
Cross-section 0.103″
Outside diameter 4.193″
Metric (ID × CS) 101.27 × 2.62 mm

OD is derived: ID + 2 × CS = 3.987″ + 2 × 0.103″ = 4.193″.

Neighboring sizes (CS 0.103″ series)

Dash ID OD ID mm vs -155
-153 3.487″ 3.693″ 88.57 ID −0.500″
-154 3.737″ 3.943″ 94.92 ID −0.250″
-155 3.987″ 4.193″ 101.27
-156 4.237″ 4.443″ 107.62 ID +0.250″
-157 4.487″ 4.693″ 113.97 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.