A single unit of heavy-gauge steel is pressed into shape, no seams or joints to cause injury. Huge 15” diameter prevents curvature of the spin, while axle-free construction eliminates risk of tail entanglement. The rolling ball bearing technology ensures the wheel spins smooth and silent. Mounts to all wire cages, finished with a pet-safe powder coat. This heavy-duty wheel is indestructible, pet owners will never buy another wheel again. Ideal for Chinchillas, Prairie Dogs, Rats, Degus, Squirrels, and other small mammals.