The durable nylon bristles and rubber nubs of the Bristle Bone provide a unique chewing experience. The irresistible, replaceable Gnawhide treat rings ensure long-lasting enjoyment and are easy to replace. The design of the Bristle Bone makes it impossible for dogs to gorge on treats. Toy unscrews to load treats and clean. Comes packed with another set of natural rawhide treats. Additional Gnawhide treat rings sold separately