A transparent design with good ventilation, this runner ball allows small animals to play comfortably. - Model Name: Runner Ball 18 - Color: Transparent - Size: Approximately 18cm in diameter - Application: Small animal toy - Features: With ventilation holes I purchased this for my baby Richardson's ground squirrel and used it twice, but it just sat there and didn't roll at all. Disinfected with alcohol gel. This item has been stored at home, so please refrain from purchasing if you are sensitive to used items. Thank you for looking.