Description: Made of high quality wood material, eco-friendly and for your pet safety. Helps your hamster exercise more and develop agility. Widened and thickened wood base provides reliable and stable mount for the exercise wheel. It not only serves as exercise toy preferred for small pet sports activities but also a nice decoration. The wooden wheel is noiseless, when pets play with this wheel, it will not disturb you. Specification: Material: Wood Size Chart: S: Outer diameter 15cm/5.9inch, inner diameter 14.4cm/5.67inch, base width 9cm/3.54inch, overall height 17.5cm/6.89inch, wheel outer width 6cm/2.36inch, inner width 5.3cm/2.09inch; M: Outer diameter 21cm/8.27inch, inner diameter 19.2cm/7.56inch, base width 12cm/4.72inch, overall height 23.5cm/9.25inch, wheel outer width 8cm/3.15inch, inner width 7.2cm/2.83inch; Package Includes: 2 Pieces Small Pets Exercise Wheel Note: Color might be slightly different due to the color calibration of each individual monitor. Please allow slightly measuring deviation due to manual measurement.