These tennis balls are made from ultra–pet–friendly materials, featuring an extra bouncy rubber core. Sold in a mesh drawstring pouch. A timeless classic. Made from ultra pet-friendly materials and with an extra bouncy rubber core that your dog is sure to love. Pairs perfectly with the Tennis Tumble for a playtime challenge. Materials Natural Rubber core wrapped in a pet-safe poly felt. Product Dimensions & Specs: Ball Diameter = 2.36", about the same size as a regulation-sized tennis ball. Note: Our toys are designed to be loved by all dogs, big and small. How long they last will depend on your dog's size, chew strength and play style.