This is the dental toy dogs love to chew! The durable nylon bristles and rubber nubs of the Bristle Bone toy encourage good dental health. Irresistible, replaceable treat rings easily slide on the sides for longer lasting playtime. Your pet can gnaw and chew on the treat rings but can't gulp or gorge on treats. The toy unscrews for easy treat loading and cleaning. 2 sets of treat rings are included. Additional treat rings are available separately.