PETKIT 4-in-1 cat scratcher, is a multi-functional activity center by day and a bed at night. A small bell in the orange tracking ball and catnip in the mint green ball serve to stimulate and attract cats. The scratch pad at the center is perfect for cats to scratch and exercise. Cats will also love to sleep on it at night. Many cats can have fun together at the same time. The scratch pad and tracking balls are all replaceable.