Fluoro-elastomer is also known as FKM FPM or VITON™ after the popular brand that manufactures it. You may see this rubber listed under different names in different places, but it is all the same. It was invented by DuPont and is now manufactured by a variety of companies around the world.
Despite being the same material, each name is the accepted name for Fluoro-Elastomer by different organizations. This is where the majority of people become perplexed. To clear the air, here is a rundown of what they are:
FKM is the American Standard ASTM short form name. It is the name given to approximately 80% of the Fluoro-Elastomers defined by ASTM D1418.
VITON™ is a registered trademark of Du Pont performance elastomers, the rubber's original developers. However, Viton is also used as a generic term for the material, regardless of who manufactures it.
FPM is the international abbreviation for Fluoro-Elastomer (1629 standard).