These specially designed rat toys are adored by small animals and are also suitable for chinchillas and guinea pigs. There are straps provided to attach it to the top of the cage if required but this toy is semi rigid on its own and can be used freestanding. MEASUREMENTS: This is a BIG toy. It can be freestanding or can hang using the clips provided. 30x30x25cm (12x12x10"). This toy will comfortably fit 4+ adult ferrets or 9+ adult rats (even cats can fit in this one - it is HUGE!).