O-Ring Selection

Certain o-ring materials offer better chemical resistance while others offer better heat resistance or cold flexibility within your application. For specific chemical properties refer to the Chemical Compatibility Guide. Some guidelines for the different types of o-rings:


The most common o-ring material is Buna-N due to its solvent, oil and water resistance. It has a temperature range of -34° to 121° C


FKM is well known for its outstanding resistance to heat, oxidation, weathering and ozone. The temperature range is -26° to 204° C.


Ethylene-propylene-diene rubber (EPDM, also sometimes referred to as EPR) is a chemically resistant family of compounds. Colder uses high quality peroxide cured EPDMs that provide exceptional resistance to temperatures with a wide range of chemicals.

FFKM (Chemraz®, Simriz®, Kalrez®)


FFKM perfluorinated elastomer seals offer the broadest range of chemical resistance of any elastomeric material, combining the resilience and sealing force of an elastomer with chemical resistance approaching that of PTFE.

PFA & FEP Encapsulated Seals

Encapsulated seals combine the resiliency of the elastomer with the superior chemical resistance of the fluoropolymer to achieve a seal that is lower cost than a pure fluoroelastomer FFKM seal.



Commonly used when food, beverages or potable water is passing through the coupling.


Slicone seals have good temperature resistance; the temperature range is -56° to 204° C.  Silicone can also be supplied to meet Class VI requirements for life sciences applications.