Moon Glow Run-About Balls provide pets and pet owners with interactive fun during playtime. Sized perfectly for hamsters and gerbils, the glowing Run-About Ball provides the perfect outlet for your pet's excess energy. Our glow-in-the-dark Moon Glow Run-About balls also make a perfect temporary area to keep your furry friend while you are cleaning their cage. For added safety, use your Run-About Ball on Super Pet's Hamtrac Raceway and provide your pet with a controlled exercise environment. 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. 7" diameter is ideal for hamsters, gerbils, or other small animals Provides interactive fun for the pet and the pet owner