The patent pending EZ Mount Track n’ Roll™ is an interactive toy that keeps cats busy batting and swatting the two balls back and forth for hours. Can be used with other K&H EZ Mount products or on its own. Encourages exercise to keep pets healthy and fit. Attaches to any glass surface such as windows or sliding doors and most appliances. Mounts to any glass surface and most appliances. Interactive balls for hours of fun. Pairs great with other K&H EZ Mount products. Perfect for glass doors, windows, or even on your fridge.