All of the Chuckit! balls are specifically designed for the most demanding use by a growing population of fetch enthusiasts. Each ball is compatible with the Chuckit! launchers, so that you do not have to bend down and pick up a slobbery ball. Tennis Balls - Give your dog something to jump for! Extra tennis balls that are high quality and designed for the game of fetch. High quality tennis balls with an extra thick rubber core, and attractive colors for improved visibility!