Buna-N (Nitrile Rubber)
This elastomer is recommended for general purpose sealing of water, petroleum oils, solvents and some alkalies. It is superior to most other elastomers with regard to compression set, abrasion and tear resistance. The maximum service temperature of Buna-N is 200°F (94°C). In 1999 Plast-O-Matic began phasing out standard use of Buna-nitrile in favor of EPDM (see below), with the exception of seals in air chambers and those used in oil-based applications when ordered specifically with Buna seals.