Penn Tour tennis balls are the #1 choice of top level players. These premium tennis balls are covered with Penn’s exclusive LongPlay® felt for extended wear, and feature our Smart Optik® high visibility felt treatment for maximum brightness. Penn’s premium line of balls are the most technologically advanced tennis balls in the world, providing players with optimum core and felt technologies for the optimum balance of consistency, longevity, and overall playability. Case of 24 (3-Ball) Cans / 72 Balls. Smart Optik® felt is 19% more visible than a standard tennis ball. A ball you can see better is a ball you can hit better. USTA and ITF approved. X-Duty Felt designed for Hard Court Use