1[170 Sheet Capacity] The plastic spiral binding coil, with a 19mm diameter, can accommodate up to 170 sheets of paper (A4, 70g). Easily add or remove pages without any hassle. 2[4:1 Pitch] The spiral binding spine features a 4:1 pitch, compatible with any binding machine that punches 4 holes per inch. Provides a secure and professional binding solution. 3[360 Degree Rotation] The binding coil allows for 360 degree page flipping, making it easier to read and allowing bound projects to lay flat. 4[For Letter Size Paper] These 48 loop binding spirals are perfect for letter sized paper (8.5x11 inch). The length of the coil can also be easily cut with scissors to suit individual needs. 5[50 Coils] The set contains 50 spiral binding coils, ensuring long term productivity for your binding projects. Easily bind your documents and have plenty left for future use. 50 x Spiral Binding Coil