Hard plastic Boingo Balls are surrounded by a crisscrossing of tough and thick rubber rings that provides easy grip and erratic bouncing. Beads inside the ball create a whirling sound that will drive pets crazy. They even float in water! The innovative, space age shape of these toys will provide you and your pet plenty of fun and exercise. Boingo Balls are available in three sizes: Small 2", Medium 3.5" and Large 5" in diameter. Small size is great for smaller dogs and even cats. Boingo Balls come in assorted colors as shown.