The hitting surface of the tennis racket is defined as the main area of the stringing pattern which is bordered by the where the strings enter the frame. The hitting surface shall by flat and consist of a pattern of crossed strings. The stringing pattern must be generally uniform and not less dense in the center than in any other area.
The racket must be designed and strung so that the playing characteristics are identical on both faces. The racket must be free of attached objects, protrusions and devices, other than those used to limit or prevent wear or vibration, or to distribute weight for the frame.
Objects used to prevent wear or vibration, or to distribute weight for the frame must be reasonable in size and placement for such purposes.