Zeus DUO chew toys have a unique, durable consistency for optimal chewing enjoyment by dogs, and are deliciously scented for extra appeal. Zeus DUO chew toys are made of a unique duo of durable, non-toxic materials to provide your dog with an optimal chewing experience. The rigid nylon center is scented and enveloped by a soft yet resilient outer layer that your dog will love sinking their teeth into, helping to prevent destructive chewing.