Color: Natural Package Included: 1* Hamster Wheel Size: Dia. 15cm/21cm/29cm Material: Wood Quantity: 1PC S Size: Outer Diameter: 15cm/5.91", Inner Diameter: 14.4cm/5.67", Base Width: 9cm/3.54", Total Length: 17.5cm/6.89" (Approx.) M Size: Outer Diameter: 21cm/8.27", Inner Diameter: 19.2cm/7.56", Base Width: 12cm/4.72", Total Length: 23.5cm/9.26" (Approx.) L Size: Outer Diameter: 29cm/11.4", Inner Diameter: 28cm/11", Base Width: 14cm/5.51", Total Length: 32cm/12.6" (Approx.) Running wheel for your loved pets. Suitable for hamsters, gerbils, chinchilla, hedgehog, guinea pig, and other small friends. High quality wood material is safe and comfortable for your pets. Also a nice decoration for the cage.