Penn 55108 Tennis Balls Hi-Intensity Yellow 3 / Can Pack of 2 cans (total of 6 balls) NA/P Imported Pack of 2 cans (total of 6 balls) Extra-duty felt is ideal for hard court play Natural rubber offers a consistent feel and reduced shock Interlocked wool fiber for longer wear; deep elastic seams prevent cracking USA/ITF approved for competitive play; official ball of USTA League Tennis