Made of Buna-nitrile (also called Buna-N) for use with a variety of fluids from petroleum to aliphatic hydrocarbons Durometer (hardness) of 90A for resistance to penetration Round cross-section to provide a seal between cylindrical overlapping surfaces For use across a wide temperature range from -30 degrees F/-34 degrees C to 250 degrees F/121 degrees C Meets standards defined by Aerospace Standard AS568A