●the Special Pingpong: Showing Hit Rate and Degree of Rotation. ●the Connecting Shaft: Ensure the Consistency of the Ball Trajectory. ●The machine adopts buckle instead of using zipper,so it is convenient to put and remove the serving machine. ●the Base: Fixed Position to Meet Different Demands of Practice. ●To Help Beginners Master the Rotation of Balls Resulted by Strokes on Different Parts and Directions.