O - Rings


An O-ring is a loop of elastomer with a round (o-shaped) cross-section used as a mechanical seal or gasket. They are designed to be seated in a groove and compressed during assembly between two or more parts, creating a seal at the interface.

The joint may be static, or (in some designs) have relative motion between the parts and the o-ring; rotating pump shafts and hydraulic cylinders, for example. Joints with motion usually require lubrication of the o-ring to reduce wear. This is typically accomplished with the fluid being sealed.

O-rings are one of the most common seals used in machine design because they are inexpensive and easy to make, reliable, and have simple mounting requirements. They can seal tens of megapascals (thousands of psi) pressure.


Material NBR, MVQ, FPM, ACM, PTFE Approved compounds
Dimensions National/ international standards
AS 568 A, AN 6227, AN 6230,
MS 29513, BS 1806, JIS W 1516, JIS W 1517, R 28 to R 88, MS 29512, BS 4518, SMS 1586, JIS B 2401, R 0 to R 27, ISO 3601/1, DIN 3771/1
general metric sizes
(form. DIN 3770)