... are the most common bearing typeDeep groove ball bearing feature1) Model: Open, Z, ZZ, RZ,2RZ,RS, 2RS 2) Quality level: reach ... 73Shield,seal and lubrication The structure of bearings consists of open and close types,and the close type might be equipped ... the conditions. Change,please connect with our engineers.Bearing collarand ball materidl The best material for bearing is high carbon chromium ...