... 3.Very smooth hand feeling 4.high-end technology auto ball bearingFeatures:High quality and good service Less frication and good ... steel, stainless steel. Etc. Precision: P0 P5 P6 Retainer: copper cage, nylon retainer, steel retainer, Bakelite retainer, etcdifferent types. such as ... series, 68series, 160series etc. for more information, please contact us ball bearing