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The garter spring is located at the end of the primary sealing lip and used to apply pressure to the sealing lip against the shaft. Common garter spring material types are:

Typically used in hydraulic high-stress applications where compounds under high pressure are exposed to wear, the benefits of polyurethane seals include: 

The most common oil seals are the ERIKS types R, RST, M and MST, which correspond respectively to types A, AS, B and BS according to DIN 3760/ISO 6194.

The lip is specially designed to ensure the oil seal works effectively with the different forces that arise during rotation. Many different designs and materials are used, so countless types of oil seals are available. These are chosen according to the application; pumps, gearboxes, wheels, and many other rotating applications where fluids need to be sealed. They are used in a variety of sectors, such as the chemical industry, manufacturing, wind turbines, automotive sector, food industry, and more. Oil seals are used in nearly all sectors.

In this kind of seal, wider tolerances are possible between the OD of the seal and the seal housing. Irregularities of the housing surface can be taken up by the resilient rubber layer on the outside of the seal. However, the rubber covered seal can be blown out under high pressure in a reciprocating application whereas, with a metal case, there is no such danger.

Obtaining adequate adhesion of fluoroelastomer compounds to metal inserts is a major consideration in fabrication of shaft seals. Adhesive systems worked out for bisphenol-cured VDF/HFP/TFE elastomers often do not perform adequately for peroxide-curable fluoroelastomers and more base-resistant polymers that contain little or no VDF. The trend toward use of more resistant fluoroelastomers in shaft seals has necessitated considerable effort on compounding and adhesive system development to get adequate bonding of the new materials. Silane-type primers are often used to coat metal inserts; these contain residual active groups such as amine functions that interact with the fluoroelastomer compound to attain good adhesion, especially for VDF/HFP/TFE elastomers. Other adhesive systems, using epoxy compounds or tie-coats, may be necessary for difficult bonding situations.³