In case the FLINGERZ™ BALL has been thrown too far and can no longer be found despite its bright colour, or if the four-legged training partner needs a second ball as a replacement object at the beginning, there is the double pack of FLINGERZ™ SPARE BALLS. Like all FLINGERZ™ toys, the balls are designed to be picked up easily and cleanly by the patented launcher stick, which allows them to be thrown particularly far without exerting too much force. (The sling stick is not included.) The robust rubber is also forgiving of excited chewing by the dog. The balls can be filled with snacks so that rewards can be given directly after the retrieve. When flying in the air, the special openings make a whistling sound that motivates the four-legged friend to chase even more. The balls are floatable and one glows in the dark, making them the perfect toy for exuberant and species-appropriate retrieve training in summer as well as in winter.