Rotary shaft seals are also known as Oil seals. They are often called grease, fluid or dirt seals. They close spaces between stationary and moving components in mechanical equipment. They are used to help prevent lubricant escape. Oil seals stop harmful contaminants from entering machinery, particularly in severe environments. They are vital components of almost every type of machine and vehicle in operation. They protect all types of precision-constructed, close-fitting ball, sleeve and roller bearings.

Rotary shaft seals help prevent lubricants from escaping the bearings or a specific area in precision bearings.

In machine components, rotary shaft seals help prevent abrasives, corrosive moisture and other harmful contaminants from entering machinery. They also help stop mixture of two different mediums such as lubricating oil and water.

Rotary Shaft seals are produced by vulcanising an elastomer to a metal ring. This acts as a stiffener, and utilises a metal tensioning spring behind the sealing lip. Many other designs can be supplied. These include, High Pressure, Dual Spring and end caps. The most common elastomer used is Nitrile.