A 2-pack of LED replacement plastic balls that may be used on their own or with the Jackson Galaxy Spiral or the Jackson Galaxy Space Station. The internal LED lights in the ball light up when batted around and turn off after 30 seconds of no activity. Designed exclusively for Jackson Galaxy.PRODUCT NOTE: No toy is indestructible. Supervise your pet when using since small parts can present a choking hazard or internal blockage. Discontinue use if the toy is damaged. Keep out of reach of children.