1. Specification: Inner diameter: 8mm/0.3'; Length: 27cm/11'; Number of binding sides: 40; Material: metal; Color: silver; Packing list: 100 pieces metal double ring wire binding combs 2. ADVANTAGE: The double ring wire binding combs are made of metal, which is both strong and durable, ensuring longterm productivity for all your binding projects. With their double ring style, they provide security and stability and offer a reliable solution to your longterm binding needs. They are designed for easy paper binding and ensure that your documents are preserved for an extended period of time. 3. INSTRUCTIONS: The spiral binding rolls have a 3:1 pitch, making them suitable for any binding machine that punches 3 holes per inch. The binding spirals provide 360degree pageturning capability for easier reading. 4. APPLICATION: These metal double ring wire binding combs are suitable for various office occasions and provide convenience for storing files, binding documents, collecting paper, etc. They are an solution for organizing your files to prevent scattering or mess. It is a portable product for office and study use.