Tuff Balls® are the first tennis ball designed specifically for dogs, and they come in bulk too! Petsport has sold these industry leading balls for over 20 years. Jr. Tuff Balls have super thick natural rubber walls for extra durability and better bounce. Jr. Tuff Balls use polyester felt instead of the wool felt found on competition balls which wears down dogs teeth. Like all Petsport products, Jr. Tuff Balls are non-toxic. They are safe for dogs and the children that play with them.