Chuckit! Erratic Ball, medium, one per pack. Squared-off corners make it bounce in a different direction every throw, so the dog has to read the ball and change course instead of running a straight line — the closest thing to a live target in a fetch toy. Durable non-toxic rubber, easy to rinse clean, gentle on the mouth, and sized to load into a medium Chuckit! launcher. Medium measures 2.5 x 3.5 x 4.5 inches. Green.