Seals are ideal for excluding dirt, dust, water or any other contaminant whilst retaining lubricant in rotary shaft equipment. They are generally used as a means of protecting the bearings of rotating shafts.

The term nitrile rubber is used for acrylonitrile-butadiene rubber (NBR). This material has very good engineering properties and is a general-purpose sealing lip material. It is a copolymer manufactured from acrylonitrile and butadiene that provides good resistance to the following media:

Most mineral oils and greases with a mineral oil base
Normal fuels like gasoline, diesel and light heating oils
Animal and vegetable oils and fats and hot water