All Court. Made with exclusive Duraweave Interlocking Fiber Technology, the Wilson Championship ball is longer lasting, more consistent and allows for less shag than any conventional tennis ball. When comparing the Wilson Championship ball’s consistency and durability to the competition, it’s clearly the choice of champions. When you take your game indoor or to the clay courts, take Wilson Championship Regular Duty tennis balls with you. Specially designed felt is perfect for the unique conditions presented by clay or indoor courts and these tennis balls deliver the consistent performance tennis players of all levels demand.