Features Practical binding method: can be tied manually by punching suitable holes, which can be easily done by any office, student group and individual. Good shine without breakage: good surface gloss, strong adhesion, wear resistance, rosiness, ageing resistance, not easy to break and fade, gentle turning can be used repeatedly. 19mm inner diameter: stationery accessories, binding accessories, inner diameter for 19mm, suitable for students and teachers. Durable with a long service life: with the durable and robust plastic binding spirals, you can easily assemble paper and store it for a longer period of time. Total 20 pieces: the package contains a total of 20 binding spirals, enough for changing and using, very practical. Specification: Item Type:Plastic Spiral Binding Bobbins Inner diameter: approx. 19 mm / 0.75 inches. Type: Stationery Accessory, Binding Accessories Package list: 20 x plastic spiral binding spools. Package List 20 x Plastic Spiral Binding Coils