Precision 521000 Hub Assembly ABS Sensors are triple tested for proper voltage and Ohm readings Triple lip seals prevent moisture and contamination from entering the bearing Induction hardened raceways are the current OEM design enhancing product life, performance and durability Hub assemblies are tested for contaminate exclusion, vibration, run out, radial and axial force and load Orbital roll form design on newer applications, Integral raceway design (GEN III) enhances product life, performance and durability