Features GREAT MATERIAL Made of high quality plastic with pretty color, not easy to deform and very durable in corrosion and long time use. FOR YOUR PAPER The spiral binding spool has an inner diameter of 16mm and allows for smoother turning of pages for reading and writing. LARGE CAPACITY Can clamp a large amount of sheets up to 130 pieces. The spine is suitable for office, classroom, library, etc. BETTER BINDING Easy to open and close. You can also cut the spine to the desired length to meet your paper storage needs. Total 10 pieces: the set includes 10 pieces spiral binding spools, and the large quantity makes it easier to replace damaged bobbins. Specification: Item Type:Spiral Binding Spool Inner diameter: approx. 16 mm / 0.63 inches. Number of holes: 30 holes. Capacity reference: 130 sheets. Package list: 10 x spiral binding spool. Package List 10 x Spiral Binding Coil