Nitrile rubber (NBR) is the general term for acrylonitrile butadiene copolymer. The acrylonitrile content of nitrile sealing compounds varies considerably—from 18% to 50%—which influences the physical characteristics of the finished material.

Of all the types examined here, Nitrile Rubber (NBR) has the best oil resistance, making it the ideal choice for a fuel transfer hose. The higher the acrylonitrile content, the better the resistance to oil and fuel. However, this may come at a cost; elasticity and compression resistance are adversely affected, and because of these effects, a compound with medium acrylonitrile content is often selected.

NBR has decent mechanical properties when compared with other elastomers, and high wear resistance. However, NBR is not ozone or weather resistant and therefore not ideal as a hose cover.