I homeschool my daughter so I am always looking for ways to keep our supplies organized. I bought this set of 20 Book Binder Rings and I was not disappointed. The set comes with 20 rings which are 2 inches in diameter and made of iron so they are strong. I use this set to help keep my daugher's daily work together so that it is easy for her to know exactly what she needs to work on for each subject. I also use them to hang scarves up in my closet. My husband wants a set to use in his workshop for various organizing tasks. I have already ordered a second set for him. These rings have tons of uses.