Fluoroelastomer is a fluorinated carbon based rubber material which is mostly used on pressure measurement equipment to seal joints between components which are either pressurised or water-tight.
FKM seals are used inside pressure sensors to seal between the pressure sensing element and the process connection assembly, they are fitted around the outside of male parallel threads to seal the connection when the threads are screwed together and they are used on electrical signal cable gland seals to keep water out.
Viton® is a well known superior brand of FKM material manufactured by DuPont™.
FKM seals have excellent resistance to high vacuums, gasoline, petrochemicals, hydrocarbons and solvents and have a working temperature range of -26°C to +200 deg C (-40 to 392 deg F).