Feature: 1. Made of high quality natural wood material, eco-friendly and has not undergone any chemical processing. 2. Fine workmanship, corrosion resistance and sturdy, durable and long service life. 3. It is not only a hamster toy, but also a fitness tool. It is also a molar tool, a natural material that has a good effect on the molars. 4. The size of each running wheel is reasonably designed and the width is much wider than the average running wheel. 5. Suitable for hamster, guinea pig, hedgehog, chinchilla and other small pets. Specification: Condition: 100% Brand New Item Type: Hamster Running Wheel Material: Wood Color: As Pictures Shown Optional Size: S, M Size S M Weight 200g 487g External Diameter(cm/inch) 15/5.91 21/8.27 Internal Diameter(cm/inch) 14.4/5.67 19.2/7.56 Base Width(cm/inch) 9/3.54 12/4.72 Height(cm/inch) 17.5/6.89 23.5/9.25 Package List: 1 x Hamster Running Wheel