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.