1. The product has three sizes, 12cm, 14cm, and 17.5cm wide. It is suitable for hamsters, hedgehogs, or other small pets 2. An ideal hamster runner can encourage them to practice, enrich their night activities, and let them enjoy running time 3.Wide Running track brings a relax back feeling, as they do not need to bend their back when running 4. There is a buckle behind the running wheel, which can be easily installed on cage 5. It is made of acrylic material, which is easier to clean than wood material. Please wipe it with a clean damp cloth when necessary