Our Grriggles FUNdamental Dog Toys are made of TPR (thermoplastic rubber) for an intriguing and interactive toy that dogs will never want to part with. These FUNdamental Tennis Bones: Have a tennis ball inside the TPR bone Are interactive - they keep dogs amused Are bouncy, flexible and chewy... and they float! Promote fitness and dental healthGrriggles FUNdamentals Tennis Bones are packaged for retail with a backer card. Coordinating FUNdamental toys are available and are sold separately. See items US2153, US2151, US2156, US2155, US2152.See the Specifications tab for product details.