four row cylindrical roller bearings 1,ABEC-3,5;Z2V2,Z3V3 ... 3,End cover:ZZ,RS 4,Noise level:Z1,Z2 four row cylindrical roller bearings is in line contact with the ... -sized and large-sized motors, electricity generators, internal combustion engines, gas turbines, machine tool spindles, deceleration devices, unloading and lifting machines ...