Fluorocarbon elastomer (FKM, widely known by the trade name Viton) is the workhorse high-temperature compound, handling continuous service to roughly 400°F (204°C) with excellent resistance to petroleum oils, fuels, many acids, and aromatic hydrocarbons. Moss Seal supplies the standard copolymer grades along with terpolymer and specialty types where improved chemical or low-temperature performance is needed, and peroxide-cured grades for explosive decompression resistance. FKM is limited in hot water and steam, in polar solvents such as ketones and esters, and in high-pH amine environments, where EPDM or evolast® FFKM is the better answer. Low-temperature capability is modest, typically around -15°F (-26°C) unless a low-temperature grade is specified.