Wide range of uses for loose-leaf, flash cards, memo filing, key rings and sample holder Closed tight, not scattered after collapse, keep your desk always organized The steel metal round rings can be split into two halves and is held together by a metal swivel rivet which is located at the center of the ring You can easily link numerous loose-leaf booklets, paper cards, name tags, instruction guides or plastic plates together How to use: The loose book ring has 2 parts and is linked together by a swivel rivet, very easy to operate, you can pull the opening to open and squeeze to close. Notes: Do not leave your children using the book rings alone, adult supervision is required. size:Line thickness 2.1mm, inner diameter 20mm, outer diameter 25mm Material:iron colour:Silver Package Contents: 100 * Binder Rings Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.