The frame of the tennis racket, including the handle and strings, shall be free of any device which makes it possible to materially change the shape of the racket.
The frame must also be free of any device that allows the racket to materially change the weight distribution that would allow it to alter the swing of inertia. The physical properties of the racket may not be changed deliberately to affect the performance of the racket during the playing of a point. No energy source may be built into, or attached to, the racket that affects the playing characteristics. The racket must be free of any device that may provide communication, advice or instruction (either visible or audible) to the player during a match.