O-Ring, Perfluoro, #014. One of the most thermally stable elastomeric materials available, Perfluoro is a family of perfluoroelastomer compounds designed to provide superior chemical resistance. Perfluoro o-rings are stocked in WHITE 75 durometer (unless otherwise noted). The effective service temperature is -7 to 230 C. Recommended for use with acids, inorganic bases, alcohols/ethers, aromatic hydro-carbons, esters, aldehydes/ ketones, aliphatic hydrocarbons, amines and chlorocarbon solvents.