Features: 1.Made of quality wood material, eco-friendly, non-toxic and safe to your pet 2.With fine workmanship, the surface is safe and comfortable to climb 3.Mute running wheel toy, providing a funny place for pets to play and rest 4.Helps your hamster exercise more and develop balance ability and agility 5.Great for hamster, mouse and other small furry animals Specification: Features: Made of quality wood material, eco-friendly, non-toxic and safe to your pet. With fine workmanship, the surface is safe and comfortable to climb. Mute running wheel toy, providing a funny place for pets to play and rest. Helps your hamster exercise more and develop balance ability and agility. Great for hamster, mouse and other small furry animals. Specification: Material: Wood Color: Wood Size (Approx.)S M External Diameter 15cm / 5.91in 21cm / 8.27in InternalDismeter 14.4cm / 5.67in 19.2cm / 7.56in Base Width 9cm / 3.54in 12cm / 4.72in Wheel Outer Width 6cm / 2.36in 8cm / 3.15in Wheel Inner Width 5.3cm / 2.09in 7.2cm / 2.83in Height 17.5cm / 6.89in 23.5cm / 9.25in Weight: approx. 240g/8.47oz Package List: 1 x Hamster Toy Note: 1. Please allow 1-2cm error due to manual measurement, thanks for your understanding. 2. Monitors are not calibrated same, item color may be showing slightly different from the real object, please take the real one as standard.