Fluorocarbon exhibits resistance to a broader range of chemicals combined with very good high temperature properties more so than any of the other elastomers. It is the closest available approach to a universal elastomer for sealing in the use of o-rings and other custom seals over other types of elastomers. Fluorocarbons exhibit low gas permeability making them well suited for hard vacuum service and many formulations are self-extinguishing. FKM materials are not generally recommended for exposure to hot water, steam, polar solvents, low molecular weight esters and ethers, glycol based brake fluids, or hot hydrofluoric or chlorosulfonic acids.The Fluorocarbon o-ring is commonly referred to as a Viton o-ring, or Fluorel, FKM, FPM o-rings. We offer a selection of both the standard black or brown AS568 o-ring and the metric o-ring.