Due to the fact that hamsters run many kilometres a day in the wild, they have a natural instinct to need to run daily. A hamster wheel is the ideal addition to any hamsters cage. Wire hamster training wheels that can stand alone or be clipped into hamster cages. Key Features: Carrier has a metal gate at the front It has a handle on top for easy carrying Available in 4 different sizes. Size Dimensions S 13 cm M 18 cm XL 27 cm