Nitrile (or NBR) O-Rings are most commonly available and are cost effective.Ideal for use as seals on pumps, drive belts, and other general engineering applications. NBR is good for applications that need to withstand fats, Greases and high temperature (+70°C). Viton® O Rings have a low compression set and have high temperature and chemical resistance.As such they are more expensive than NBR O Rings . Temperature range -20ºC to +200ºC (avoid prolonged use at higher extremes)