Double row angular contact ball bearing can be submitted radial and axial loading speed is quite high,it is non-separated type of bearings compare with the single row angular contact ball bearing,the double row angular contact ball bearing has high rigid can be submitted to bidirection of axial load,the bearing could supply with the four row cylindrical bearing together to limit the working roll to move in axial direction the double row angular contact ball bearing could apply with other bearings as a position bearing.