Nitrile is the most cost effective and commonly available O ring seal material. Ideal for use as seals for pumps, drive belts, and other general engineering applications in the hydraulic and pneumatic industry. NBR is good for applications where the O ring is exposed to fats, greases and animal or vegetable oils. For applications requiring contact with diesel or temperatures higher than 120°C you may wish to consider a Polymax FKM (Viton®) O ring seal.