For use inside a cage. This type attaches to the top of the cage. The inside of the cage will become as cute as a birch forest (*˘︶˘*).｡* These are perches made from natural white birch trees from Hokkaido. Because they are natural white birch, they have thin bark attached. Some birds will enthusiastically peel off the bark and play with it. The best size for Java sparrows to budgies. Support length: 36.5cm Support thickness: 2.4cm diameter Perch thickness: 1.4cm diameter Perch lengths: 15cm, 12.5cm, 13.5cm