This specification covers a butadiene-acrylonitrile (NBR) rubber in the form of molded rings. These rings have been used typically as sealing rings in contact with diester synthetic lubricants in service up 150 degrees C (302 degrees F), but usage is not limited to such applications. The cross-section of such rings is usually not over 0.275 inch (6.98 mm) in diameter or thickness.
