This item is manufactured with premium metal for and use. It is great for variety of uses such as loose-leaf, memo filing and sample holders. Besides, it can also be used as a keychain for you to hold keys and decorative pendants on your bag. Feature - Color: Silver. - Material: Metal. - Size: Inner Diameter:25mm. Outer Diameter: 30mm. - The metal book rings are great for variety of uses such as loose-leaf, memo filing and sample holders. - Made of metal, the loose leaf rings are and won't crack or split. - It can also be used as a keychain. - Easy to use: pull to open, squeeze to close, lock for additional security. - Great for variety of uses such as loose-leaf, memo, key rings, invoices, and sample holders. - Made of tough steel which is enough to stand the test of time. Heat treated nickel plated on the surface, won't crack or rust easily. - Dear buyer, Due to lighting effect,monitor's brightness,manual measurement and etc, there could be some slight differences in the color and size between the photo and the actual item. Sincerely hope that you can understand! Thank you! Package list: Loose Leaf Binders