Super Pet Run-About Balls provide pets and pet owners with interactive fun during playtime. Sized perfectly for hamsters and gerbils the 7 inch Moon-Glow Run-About Ball actually glows in the dark for those night time adventures. Durable glow in the dark plastic construction features a lock tight lid for safety. Moon-Glow Run-About balls also make a great temporary holding 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.