AS568-018 O-Ring

Inside diameter 0.739″
Cross-section 0.070″
Outside diameter 0.879″
Metric (ID × CS) 18.77 × 1.78 mm

OD is derived: ID + 2 × CS = 0.739″ + 2 × 0.070″ = 0.879″.

Neighboring sizes (CS 0.070″ series)

Dash ID OD ID mm vs -018
-016 0.614″ 0.754″ 15.60 ID −0.125″
-017 0.676″ 0.816″ 17.17 ID −0.063″
-018 0.739″ 0.879″ 18.77
-019 0.801″ 0.941″ 20.35 ID +0.062″
-020 0.864″ 1.004″ 21.95 ID +0.125″
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.