Features： 1、[High Capacity] The plastic spiral binding coil has a diameter of 38mm and can hold up to 310 sheets of paper (A4, 70g), allowing for easy addition and removal of pages. 2、[4:1 Pitch Compatibility] The spiral binding coil features 4:1 pitch, making it compatible with any binding machine that punches 4 holes per inch. 3、[360 Degree Rotation] With the ability to rotate 360 degrees, this binding coil allows for effortless page flipping and reading, making it easier to work with bound projects. 4、[18 Pcs Set] Each pack includes 18 spiral binding coils, ensuring long term productivity for all your binding projects, enabling you to effortlessly bind papers and store them securely. 5、[Versatile Application] Ideal for letter sized paper (8.5 x 11 inch), the length of the spiral coil can be easily cut with scissors. for engineering documents, business projects, office documents, and university presentations. Specification： Item Type: Spiral Binding Coil Material: PVC Plastic Binding Diameter: Approx. 38mm / 1 1/2in Binding Capacity: 310 Sheets (A4, 70g) Number of Loop: 48 Pitch: 4:1 Package List： 18 x Spiral Binding Coil