Add a Play Gym Toy to your Play Gym! Bottlebrush Play Gym Toys attach easily to any Bottlebrush Play Gym by simply screwing them into the pre-installed hardware. They consist of a solid piece of Copper (not steel) as the center, onto which nice chunks of Bottlebrush wood, rawhide, and other goodies are placed for your Birds to enjoy. They also help make your Parrot feel more secure on his gym by giving him a little over-head cover. You can refill the toy by unscrewing the bottom section and refilling with vine balls, Bottlebrush Bag of Bird Toy Wood parts, Rawhide, or just about anything else you can slide down the copper center. Even if you have another type of wood bird play gym or bird play stand or activity center, you can still use this toy with a minor modification.Bottlebrush wood is far superior to other types of wood on the market because it actually allows your bird to gnaw. The outer bark is soft, chewy, and easy to stand on. Your parrot"s feet were designed to naturally mesh with the bark of trees and allow him to move about effortlessly. Other woods are always too hard or too soft, but Bottlebrush fits right in the middle. Parrots need to chew, and the bark of Bottlebrush wood is absolutely perfect for chewing. Underneath all that lovely soft bark is the hard inner layer. This layer is tough enough to allow your bird to gnaw on it, but will not damage or injure his beak. All birds need to be able to gnaw on a tough (but not too hard!) wood in order to keep their beaks conditioned and shaped.