General description Solid running surface, completely safe for your pet's tail and feet. This small and cute exercise wheel is designed for hamsters, pet rats, and other small animals, providing them with an opportunity to explore, climb, and stay active. Technical specifications Material: Plastic wheel + steel bearing Diameter: 17.5 cm / 6.83 inches Usage Encourages exercise and keeps your pet healthy and active. Helps train your pet's toes and nails. Greatly arouses your pet's interest in exercising.