O ring is an annular rubber seal with a circular cross section, mainly used in mechanical parts in static conditions to prevent the leakage of liquid and gas. In some cases, O ring can also be used as the dynamic sealing element in axial reciprocating motion or low-speed rotational motion.

O ring provides as an effective and economical sealing element in different types of static or dynamic seal applications. It is a two-way sealing element. Initial compression in radial or axial direction during installation gives the O ring the own initial sealing capability. The sealing force which is produced by the system pressure and the initial sealing force increases when the system pressure increases. O ring shows outstanding performance in static sealing applications. However, in dynamic applications, they are often used as well, but their performance is limited due to the speed and pressure.

JST can offer O rings in different rubber materials such as FKM, NBR, HNBR, etc. Metric size and imperial size is available per customers' demand.

If there is any gas, choose RGD (Rapid Gas Decompression) resistant material. The RGD O ring is the competitive product in oil & gas industry. JST has HNBR, FKM materials passed the RGD test, as well as NORSOK M-710 H2S immersion test.