FKM and FPM are fluorine rubber, but FKM is the European spelling abbreviation, FPM is the American spelling abbreviation.

Fluororubbers can be divided into three basic types: fluorocarbon rubber, fluorosilicone rubber, fluorophosphoronitrile rubber.

Fluorine rubber is a special synthetic elastomer. Carbon atoms on its main chain or side chain are connected with fluorine atoms 

with strong electronegativity. Due to the large C-F bond energy (485KJ/mol) and the covalent radius of fluorine atoms is 0.64A, 

which is equivalent to half of the length of C-C bond, fluorine atoms can shield the C-C main chain well and ensure the stability 

of the C-C chain. So that it has other rubber incomparable excellent performance, such as oil resistance, chemical resistance, 

good physical and mechanical properties and weather resistance, electrical insulation and radiation resistance, etc., in all 

synthetic rubber, its comprehensive performance is the best, commonly known as "rubber king".