- Features: O-shaped sealing ring is widely used in various dynamic and static sealing occasions because of its low manufacturing cost and convenient use.
- Standards: Most countries have formulated a series of product standards for O-ring seals, among which American standards (AS 568), Japanese standards (JIS B 2401), and international standards (ISO 3601/1) are more common
| Standard | O-ring section diameter w |
| American standards AS 568 | 1.78 2.62 3.53 5.33 7.00 |
| British Standard BS 1516 | |
| Japanese standards JIS B 2401 | 1.9 2.4 3.1 3.5 5.7 8.4 |
| International standards (ISO 3601/1) | 1.8 2.65 3.55 5.30 7.00 |
| German standard DIN 3771/1 | |
| Chinese Standard GB 3452.1 | |
| Preferred metric size | 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 6.0 7.0 8.0 10.0 12.0 |
| American standards AS 568(900series) | 1.02 1.42 1.63 1.83 1.98 2.08 2.21 2.46 2.95 3.00 |