Specially designed to make exercise easy for dwarf hamsters and mice, these perfectly sized Run-About Balls allow tiny pets to maneuver with greater ease. Mini Run-About balls also make a great temporary area to keep your little critter while you are cleaning their cage. Encourage healthy exercise in a secure and safe way. Makes a great temporary holding area to keep your furry friend while you clean their home. 5" diameter ball is ideal for dwarf hamsters, mice, or other small animals. Provides interactive fun for the pet and the pet owner.