If you have a cockatoo or african grey, this type of foraging bird toy is a must have! Endless, indestructible entertainment is what you get with this great foraging bird toy! Great for both medium and large birds, so you can alternate if you have both. I have a goffins and a moluccan, and they both would rather unscrew nuts and bolts to forage for food then to chew on a wood toy. All parts on this toy are dishwasher safe. The bolts and wing nuts are stainless steel to last a lifetime. It will come pre-filled with everyone's favorite Nutriberries, and it's very easy to refill after these are gone. You can put seed, pellets, other treats, fun little toy parts, just about anything inside. Your bird can see them, but they have to undo the wing nuts, and pull out the bolts in order to get to them. This foraging bird toy can have several different levels of fun by simply taking away the wing nuts and bolts, or taking away the beads inside. The holes in the clear tube are 5/8" in diameter, and have smooth, safe edges.