NSK 51BWD01 Wheel Bearing Premium OE technology - Vehicle specific fit-form and performance Long life low friction bearing - Superfinished precision matched bearing raceway Water and contamination resistant - Advanced multi-lip seal technology Zero Maintenance - Sealed for life design with premium all weather grease Immediate response ABS sensor - Integrated World Class magnetic encoder seal Easy and reliable preload setting. Easy mounting process. No spacer required. No grease packing required. Compact. Integral high performance seal. Easier and more reliable preload setting. Easy mounting process. No need to press fit into knuckle. Integral Sensor rotor is optional. Preset optimum preload (for non driven wheels). Easy mounting process. High rigidity. Easy incorporation of ABS sensor.