APPENDIX K ITF RULES OF TENNIS approved as Player Analysis Technology, or that are utilised to limit or  prevent wear and tear or vibration or, for the frame only, to distribute  weight, are permitted. All permissible objects, protrusions and devices  must be reasonable in size and placement for their respective purpose(s). No energy source that in any way could change or affect the playing  characteristics of a racket may be built into or attached to a racket. Player Analysis Technology is equipment that may perform any of the following  functions with respect to player performance information: APPENDIX III PLAYER ANALYSIS TECHNOLOGY  1.  Advertising is permitted on the net as long as it is placed on the part of the net  that is within 3 feet (0.914 m) from the centre of the net posts and is produced  in such a way that it does not interfere with the vision of the players or the  playing conditions. A mark (non-commercial) of the sanctioning body is permitted on the lower  part of the net, minimum 20 inches (0.51 m) from the top of the net, as long  as it is produced in such a way that it does not interfere with the vision of the  players or the playing conditions. 2.  Advertising and other marks or material placed at the back and sides of the  court shall be permitted unless it interferes with the vision of the players or  the playing conditions.  3.  Advertising and other marks or material placed on the court surface outside  the lines is permitted unless it interferes with the vision of the players or the  playing conditions. 4.  Notwithstanding paragraphs (1), (2) and (3) above, any advertising, marks or  465 APPENDIX IV ADVERTISING A. Recording B. Storing C. Transmission D. Analysis E.  Communication to a player of any kind and by any means Player Analysis Technology may record and/or store information during a match.  Such information may only be accessed by a player in accordance with Rule 30.