SIMMERRINGS - Rotary shaft rings are rubber seals fitted with steal Radial shaft seals are used to seal rotary elements, such as a shaft or rotating bore, common examples include strut seals, hydraulic pumps seals, axle seals, power steering seals, and valve stem seals. They can work in a liquid or solid grease, oil or water in pressure up to 0,1 MPa and temperatures from -30 to +110 °C.

The seal consist of a sprung main sealing lip which has a point contact with the shaft. The point contact is formed by two angles, with the air side angle usually less than the oil side angle. Depending on the seal type these two angles are varied to create a pressure distribution at the seal contact point which has a steeper slope on the oil side of the seal. The shallower the slope on the oil side of the seal the wetter the seal will run. The spring is positioned such that axially the centerline of the spring is biased to the air side of the lip contact point. In order to exclude contaminants numerous types of dust lips or exclusionary lips may be used. There are different seal design for similar applications is a rotating face seal.