Viton, also referred to as FKM or FPM, is a fluorocarbon elastomer having excellent mechanical and physical properties. All FKMs contain vinylidene fluoride as a monomer. It exhibits outstanding resistance to oils, lubricants, mineral acids, salt solutions, blended aromatic fuels and straight aromatics as well as halogenated hydrocarbons. The effective temperature range is -20ºF to +500ºF with limited service to +600ºF. 
FKM is the designation for the fluoroelastomer category according to ASTM 1418. FPM is the international abbreviation according to DIN/ISO 1629.  Viton® is the registered trade mark of DuPont Performance Elastomers.