FATPET Small Animal Run-About Pet Exercise Ball for Hamster and Mouse Transparent design for running surface on exercise wheel provides pets with a visible and controlled exercise environment Encourage healthy exercise in a secure and safe way, and can help your pet to lose weight Specially designed for quiet spinning, and can't bother you at all Makes a great temporary holding area to keep your furry friend while you clean their home Measure: 14cm x 13.1cm x 15.5cm / 5.5" x 5.1" x 6.1"