The Pro Penn Marathon tennis ball has been named by many the longest lasting ball thanks to the exclusive Encore™ technology which provides tremendous durability without losing the feel and playability for a long time. Furthermore, the ball brings increased suitability for hard courts and provides extensive visibility as well as greater durability thanks to the LongPlay® felt. The ball has been the official tennis ball of the Professional Tennis Registry and it is supplied as a large bundle featuring 72 balls in total (12 dozen).