Hamiledyi 120 pcs Plastic C-Clips Hooks Chain Links C-Links Rat Parrot Bird Toy Cage DIY Plastic C-Clips Hooks Chain C-Links Sugar Glider Rat Parrot Cockatoos Cockatiels Inner diameter: 8mm Reusable, easy to put on and remove. Beautiful id tags to identify similar birds. They can be open wider to suit your birds. Use them to keep different breeds apart, mark suspected cockerels, seperating hatches.