Zanies® Cosmic Cones are made of dense, hard rubber, designed to withstand even the most aggressive chewers. Fun cone shape is easy to grab and ideal to gnaw to encourage dog’s natural chewing instinct. Grooved design helps clean teeth and stimulate gums and the dimpled surface adds textural interest. Hollow center can be filled with treats to add an intellectual challenge for dogs prone to separation anxiety. Available in Galatic Green, Sky Blue, Rocket Red. Toys are in three sizes: 4" Rocket Red; 5" Sky Blue; 6" Galatic Green. Diameter of hole: 3/4"