The Double Whammy Bat’s patented fling or swing design allows you to bat the ball in a traditional way or you can fling the ball (similar to lacrosse) using the patented feeder cavity design. The Double Whammy™ comes equipped with a ball retriever to eliminate the need to bend down and pick up the balls dropped at your feet by your pooch. The bat also acts as a self storage unit for tennis balls (one is included with the set).