Wilson Tour Premier All Court Tennis Balls 4 pcs WRT119400 Properties: Wilson Tour Premier tennis balls are a professional set that will help you win game after game. Pressurized balls are extremely durable. The highly visible yellow felt of Yellow Optivis guarantees excellent visibility. The ITF certificate confirms the excellent parameters of the ball, which is suitable for play on hard courts and clay. The set includes 4 Wilson tennis balls packed in a practical tube.