BOOMER BALL POWERFUL PURSUIT TOY ? Virtually indestructible ? For macho dogs that love to conquer ? Ideal therapy for bored animals ? Impact resistant ? 20" have a screw-in plug to insert pebbles for rattly fun 5 Sizes: 4", 6", 8", 10", 20" BOOMER BALL Too many toys just can't take the strain The Boomer Ball is virtually indestructible and is designed for those larger than life characters who love to chase and conquer - like Bull Terriers and other macho breeds It is designed not to be picked up by the dog and should be a size bigger than the dog can carry It can also be a therapeutic toy to enrich the environment of elephants, pigs, polar bears or any other bored, manipulative animal