Features: Advantage: Made of high quality metal can withstand heavy use, color unfading, beautiful and anti-rust, rings open and close easily and lock for extra security. Flexible design: Each one is well-designed, namely, it can be split into 2 halves and connect with a metal swivel nail tightly; So the book binders lock safely and tightly enough. Use for clip ring gate for key, installing shower curtain or loose leaf. Use: These metal binder rings suitable for classroom, company, office or home to fastening document stack, notebooks, paper cards, home organization, binding recipe, sample book, loose-leaf booklets, contract or file etc. Easy to Operate: Pull to open and squeeze to close, snap hinged binder rings with a locking mechanism that opens easily to add or remove materials.for ideal for fastening any size document stack and keys and swatches. Vintage design: Bamboo joints shaped loose leaf binder is very Creative, elegant and retro, suitable for DIY Album, keychain, scrapbooking, crafts and gift, journals, memo filing binding. Specifications: Material: Metal 20mm Inner Diameter: Approx. 20mm/0.79 inches 30mm Inner Diameter: Approx. 30mm/1.18 inches Type: 20mm Golden, 30mm Golden, 20mm Retro Dark Green Brass, 30mm Retro Dark Green Brass Package Includes: 2 Package Optional: Package A: Includes 7 Pieces Loose Leaf Binder Rings (20mm Inner Diameter） Package B: Includes 10 Pieces Loose Leaf Binder Rings (30mm Inner Diameter） note: 1.Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. 2.Due to the difference between different monitors, the picture may not reflect the actual color of the item.