The large busy bird ball is a treat dispensing roll toy your bird will love. The clear ball lets your bird see what treat is inside and when rolled, the treats will dispense randomly. There is a colorful wood bead inside that makes a fun noise and is appealing to your bird. You can use a wide variety of treats, food, trail mix or veggies, you can even put small toys inside for your bird to work for. The small ball is recommended for medium to large birds and is approximately 4 1/2" in size.