Basic features: - simple design - inseparability - easiness of assembly - high rates of rotation, especially for smaller and narrower series - possibility of radial and partial axial load transfers in both directions Versions: - with one or two side rubber seal RS, 2RS - with reinforced one or two side rubber seal RSR, 2RSR - with one or two side metal shields Z and ZZ (2Z) - with a snap ring groove in outer ring N - with a snap ring groove in outer ring and external snap ring NR - in different radial clearances C5, C4, C3, C2 - in many combinations of the above mentioned versions