The US Society of Automotive Engineers (SAE) Aerospace standard AS568 900 series is one that specifies the inside diameters, cross-sections, tolerances, and size identification codes (dash numbers) for O-rings used in sealing applications and for straight thread tube fitting boss gaskets.
| AS568 900 Series Size | ID (mm) | ID Tol' (+/- mm) | CS (mm) | CS Tol' (mm) | ID (inch) | ID Tol' (+/- inch) | CS (inch) | CS Tol' (inch) |
|---|---|---|---|---|---|---|---|---|
| AS568 -901 | 4.7 | 0.13 | 1.42 | 0.08 | 0.185 | 0.005 | 0.056 | 0.003 |
| AS568 -902 | 6.07 | 1.63 | 0.239 | 0.064 | ||||
| AS568 -903 | 7.65 | 0.301 | ||||||
| AS568 -904 | 8.92 | 1.83 | 0.351 | 0.072 | ||||
| AS568 -905 | 10.52 | 0.414 | ||||||
| AS568 -906 | 11.89 | 1.98 | 0.468 | 0.078 | ||||
| AS568 -907 | 13.46 | 0.18 | 2.08 | 0.530 | 0.007 | 0.082 | ||
| AS568 -908 | 16.36 | 0.23 | 2.21 | 0.644 | 0.009 | 0.087 | ||
| AS568 -909 | 17.93 | 2.46 | 0.706 | 0.097 | ||||
| AS568 -910 | 19.18 | 0.755 | ||||||
| AS568 -911 | 21.92 | 2.95 | 0.1 | 0.863 | 0.116 | 0.004 | ||
| AS568 -912 | 23.47 | 0.924 | ||||||
| AS568 -913 | 25.04 | 0.26 | 0.986 | 0.010 | ||||
| AS568 -914 | 26.59 | 1.047 | ||||||
| AS568 -916 | 29.74 | 1.171 | ||||||
| AS568 -918 | 34.42 | 0.3 | 1.355 | 0.012 | ||||
| AS568 -920 | 37.47 | 0.36 | 3 | 1.475 | 0.014 | 0.118 | ||
| AS568 -924 | 43.69 | 1.720 | ||||||
| AS568 -928 | 53.09 | 0.46 | 2.090 | 0.018 | ||||
| AS568 -932 | 59.36 | 2.337 |