Nitrile rubber is a synthetic rubber formed by polymerization of acrylonitrile with butadiene. It performs well in carburetor and fuel pump diaphragms, aircraft hoses, seals and gaskets as well as oil-lined tubing. Nitrile rubber is more resistant to oils and acids compared to natural rubber but is not as strong or flexible. In addition to its excellent elastomeric properties, it is resistant to oil, caustics, and aliphatic hydrocarbons. Nitrile rubber can be hydrogenated in solution using precious metal catalysts. Hydrogenated nitrile rubber (HNBR) has an intriguing combination of properties. Just as other elastomers, the material has high tensile strength, low permanent set, very good abrasion resistance and high elasticity.