Application: These metal twin loop wire binding spines are suitable for various office occasions and provide a great convenience for file storage, file binding, paper collection, etc. They are a great solution for organizing your files, preventing them from being scattered or causing a mess. It is a portable product for office and study.Note: These 3:1 pitch wire binding spines are not suitable for machines.Instruction: Spiral binding coils have a 3:1 pitch, making them suitable for any binding machine that punches 3 holes per inch. Binding spirals provide a 360-degree page-turning rotation capability for easier reading.Advantage: The twin loop wire binding spines are manufactured from metal, which is both strong and durable, ensuring long-term productivity for all your binding projects. Featuring a double-loop style, they offer security and stability, providing a reliable solution for your long-term binding needs. They are designed for easy paper binding, ensuring your documents are preserved for an extended period.Specification: Inner diameter: 10mm/0.4inch; Length: 27cm/11 inch; Number of binding pages:60; Material: Metal; Color: Silver; Packing List: 100 Pcs Metal Twin Loop Wire Binding Spines.