Designed for the most demanding use by fetch enthusiasts-these are not ordinary balls for dogs. The Chuckit! Whistle Ball is made from natural rubber. The easy to clean ball is designed with holes that twitter and whistle while the ball is in flight, providing stimulating, fetching fun. The fun, high-quality interactive balls promote activities for canine fitness which will enhance the human-canine bond. Available in 3 sizes; Small (2 pack), Medium (2 pack), and Large (single). Colour is assorted