The Z cover disc is firmly pressed into the outer ring. As a non-abrasive seal, it does not generate any additional friction. The 2RS seal is the most commonly used rubbing seal. It consists of NBR (acrylonitrile butadiene rubber) as standard and is reinforced with sheet steel on the inside to create the necessary rigidity. This model is clamped in the same groove as a Z cover disk in the outer ring and, depending on the version, rests on the inner ring with one or more sealing lips. Due to the flexible material NBR, the seal can be easily removed.