This Boomer Ball has a rigid sidewall, made of non-toxic hard plastic, which is resistant, but not impervious, to chewing and scratching. The roughened surface on a used ball may be smoothed with a carpenter's rasp, file, or rough sandpaper. Suited for large breeds and heavy chewers like dobermans, rottweilers, pit bulls, and german shepherds.
Removable plug can be used to fill the ball with water, sand, or pebbles to add sensory play.
 
Boomer Ball - 10 Inch: Ball weight 2 - 3 lbs. 
Boomer Ball - 10 Inch Heavy Duty Challenger - Ball weight 3.5 - 5 lbs.