Penn Plax Plantation Rubber Ball is very canine friendly! Each Ball is made of tough, elastic gum rubber with 'pimples' on the outside and a bell on the inside. The design makes it easy for your friend to pick up and play with, and the 'pimples' massage the gums while playing. This is a great ball for any game of fetch with your friend! Each Ball comes in assorted colors and is approx. 2" in diameter.