PRODUCT UPDATE: Catstages recently updated the Tower of Tracks product to include six 1.5"-balls (38mm) instead of 3 at no extra cost to you. Due to available stock at Amazon's warehouses, customers may receive the 3-ball version of Tower of Tracks. MENTALLY ENGAGING TRACKS TOY: This interactive cat toy is designed with 3 levels of tracks and 6 brightly colored moving balls to attract kitty’s attention! Your cat will adore batting, swatting, and pouncing the bright colored balls as they engage their natural instincts to hunt. GREAT FOR SINGLE & MULTIPLE CAT HOUSEHOLDS: Whether you have one cat or more, the Tower of Tracks will keep your furry friends enticed with bright colors and spinning balls. UNIQUE SAFETY BAR DESIGN: A small safety bar across the top central opening keeps overly curious kitties from getting stuck while playing with this track toy. STURDY CONSTRUCTION & NON-SLIP BASE: Durable plastic and a non-slip base hold the Tower of Tracks in place during vigorous play. PLAY IT SAFE: No toy is indestructible. Do not leave toys with unsupervised pets. Remove and replace toy if damaged.