This Komet Krawler Exercise Ball features safe and durable shatter resistant plastic construction. It provides pets with the freedom to roam and explore while they are safely confined in the exercise ball. Watch as your favorite pets quickly learn to maneuver around common household obstacles with ease. Ribbed interior allows for better traction. Plenty of ventilation slits for the comfort of your pet. Dwarf sized Kritter Krawler Exercise Ball is perfect for dwarf hamsters and pet mice.