Chuckit! Erratic Rubber Ball Fetch Dog Toy Medium (2.5 ) for Medium Dogs 20-60 lb Pack of 2 Green - Designed for the most demanding use by a growing population of fetch enthusiasts these are not ordinary balls for dogs.Chuckit! Erratic Ball is a durable geometrically shaped rubber ball that bounces erratically to keep the game interesting and challenging for your dog. Squared corners cause the ball to bounce every which way when thrown. Made from durable rubber. Easy-to-clean. Made just the right size for use with your Chuckit! Launcher. These high-bouncing erratic balls are available in sizes small medium large x-large and xx-large with one and two-pack options.