[Rustproof & Long-lasting]These metal binder rings with multi-layer nickel-plated finish are rustproof, strong and durable.It is laser polished to a smooth finish so it will not scratch the hand when opened. Each binder rings support opening for more than 10000 times. [Standard Size]The package includes 80 Pcs loose leaf binder rings. Outer diameter: 25mm (1 inch), inner diameter: 20mm (0.8 inch). Each binder ring can hold up 140 sheets loose leaf papers. [Easy To Open/Close]Easy to use. Hold ends of the opening with both hands, then push forward with one hand and backward with the other with a little force. The rings will firmly hold your flashcards or papers without loosening. [Extensive Use]These small binder rings are widely use for loose-leaf, flash cards, books, papers, memo filing, keychains, and more. Keep your small items in order. [Lock Tight] The movable opening of the binder rings adopt a tight lock design, which will not be dislocated when opening and closing. It will keep the paper in place even if the papers are moved by a large margin.