Special Tennis Training Machine fits for single person to train in your yard or tennis courts. Fill water to keep the foundation stay stabilized and can play your single tennis without pick up your balls. Ball can come back through the elastic cord after you hit out it. It can save your time to collect balls. You deserve to own this!! With plastic pedestal, a ball and elastic cord. Balls cover with woolen and with rubber bladder inside. Fits for Junior Aldut for training. Measure: 2.5 inches. The tennis balls are high elasticity, high stability and resistance to play.