1Size and Capacity: The spiral binding coil has a diameter of 16mm (5/8in), can accommodate up to 140 sheets of paper (A4, 70g), making it easy to add and reduce paper. 2Coil Specifications: These spiral binding spines are single wire and 48 loops design, with 4:1 pitch, which is compatible with any binding machine with 4 holes per inch. 3Durable Material: These single wire binding coils are made of excellent metal material, sturdy and durable, allowing you to easily bind paper and store it for a long time. 4Convenient Use: These paper binding spines support 360 degree page turning function, making your binding items flat and easy to read, improving work efficiency. 5Applicable Range: Includes 100 spiral binding coils, suitable for 8.5x11 inch paper, can be cut according to needs, used for binding engineering documents, office files, etc. 100 x Spiral Binding Spines