Of the vast selection of different O-Ring dimension standards, the United States' most popular is AS568. It was formerly known as ARP 568, and is currently maintained by the Society of Automotive Engineers. AS568 lists 369 sizes of O-Rings with corresponding dimensions and tolerances. This standard offers O-Rings in five different cross-sections, whose inside diameters range from 1/32" to 26". Tube fitting boss seals are included in AS568 as "-900" series O-Ring sizes, and are specified for use in MS33649 (now superseded by SAE-AS5202) straight thread tube fittings.
High Performance Seals also offers a wide selection of metric and non-standard O-Rings. As a subset of the available metric sizes, we stock many Japanese Industrial Standard (JIS B2401) sizes. If a special size or specific chemical resistance is required, High Performance Seals can provide custom O-Rings specially made to your demanding requirements.
For more information about O-Ring sizes, please see the o-ring size chart.