1Paper Capacity: These double loop wire binding spine can accommodate up to 180 sheets of A4 paper, a total of 70g, meeting your needs. 2Metal Inner Wire: The interior of the binding loop is iron wire, which is sturdy and durable, allowing you to easily fix paper and store it for a long time. 3Nylon Coating: The exterior is nylon coating, with good surface gloss, corrosion resistance, wear resistance, and long service life. 4Perfect Size: Each binding spine has a diameter of 3/4in and a thickness of 0.8mm. Each spine has a pitch of 3:1 and 34 double loops, which supports 360 degree rotation. 5Binding Lines: These double loop binding wires can be used to bind important documents, files, or reports for upcoming presentations or projects. 50 xDouble Loop Wire Binding Spine