The secret of the Chewbers durability? The rubber is molded with a reinforcing nylon mesh for increased tensile strength. TESTIMONIAL: My one and a half year old Pit Bull 'Cyrus', loves playing fetch and I wanted to get her a Frisbee but I knew it wouldn't last. Well, the Chewber has far outlasted my expectations and Cyrus loves it and the water dish feature is great for when we're at the park. Thanks for a great product.