Check the listing for details. Totiyea 50 Pack Plastic Spiral Binding Coils20Mm(3/4) Binding Spirals170 Shee. Condition: New. Listed at 25.75 USD. 20mm(3/4") Plastic Spiral Binding Coils ,4:1 Pitch, Black Sheet Capacity:170 sheetsSpine Diameter:20mm(3/4") Package Contain:50 binding coilsLength:about 12",fit for A4&Letter Size（8.5x11"）Plastic spines/spiral /coils are made by precision equipment from well-experienced manufactory. Products are created by high-quality raw material to achieve hard form and good color fastness over time. Binding coils are used in engineer file, business project, office documents, university presentations and more. A lay-flat design with the ability to flip pages 360° from front to back. The 48 loops plastic coils in black fits letter sized paper(8.5x11") 4:1 pitch 4 holes per inch. Compatiable with any standard 48 loops plastic coils-binding system.Turn your loose documents into a professional-looking report worth presenting with Plastic Spiral Binding Coils. 50 Per Box: A box of 50 Spiral Binding Coils ensures long-term productivity for all of your binding projects,allow you to bind paper sheets with ease and store for a long time. 170-SHEET CAPACITY:Plastic Spiral Binding Coils measure 20mm(3/4") in diameter,perfect to add and subtract paper sheets,can hold up to 170 sheets. FOR LETTER SIZE&A4: Length of Spiral Binding Coils is approx.12" ,can be used with letter size paper (8.5x11") or standard A4 size paper (8.3x11.7") 4:1 PITCH:Spiral Binding Coils(48 loops)are designed with a 4:1 pitch, fit any 4-holes-per-inch coil-binding machines. 360 Degree Rotation:Plastic Spiral Binding Coils allow 360 degree page-turning rotation capability for easier reading,bound projects can lay flat.