As we all know, hamsters love to run, while a hamster exercise ball is a great way for your little pal to get exercise and encourage them to explore, providing the perfect outlet for your pet’s excess energy. Nobleza hamster exercise ball comes in φ5.5 inch and φ7 inch for choice, suitable for dwarf rodent breeds or small and medium-sized rodents usage. In order to ensure your rodent can enjoy a comfortable ride, please must measure your small pets accordingly before placing an order, to make sure whether the size fits your small pets.