Mammoth Tirebiters are made real-tire tough from specially formulated natural rubber with two-ply nylon. Perfect for interactive playing, tossing, and tugging. Key Benefits for strong chewers. Made real-tire tough. Natural rubber with two-ply nylon. For interactive playing. Safety tested non-toxic for dogs. Sizes Mini: 3.5". Small: 6". Medium: 8". Large: 10".