Product SizeHamster Exercise Ball diameter measures 10cm/3.94inch, Suitable for dwarf hamsters, sugar gliders, ferret and other small animals. Quality MaterialOur hamster running balls is made of high quality materials, odorless, strong and durable, not easy to wear and tear. TransparentThe transparent of the hamster exercise ball is convenient for the owner to observe the state of the pet, and you can play with your pet to add more fun. Breathable Running BallsThere are multiple vent holes on the ball to keep the air in the ball fresh. Easy to InstallClose the two hemispheres and fasten them; put the hamster in, aligning the hidden button of the lid with the corresponding position of the running balls, and then tighten the lid. Specification: Material: PP Diameter:10cm/3.94inch Package Includes: 1Hamster Exercise Ball Note: Please allow slightly errors due to manual measurement and different monitors.