TruBind 8-mm (5/16-inch) Binding Coils - COIL08 - Durable - 4:1 Pitch (4 holes/inch) - 12 Inches Long - Pre-Sized to Fit Letter-Sized Paper - Compatible with TruBind Binding Machines - 100 per Box QUALITY PLASTIC - Easily create bound projects that lay flat with our binding coils. Their durable plastic construction wont bend or snag, and they look great on business proposals, reports, menus, and more. PRECUT COILS - Each TruBind coil is 12 inches long and fits a letter-sized book, document, or binding project perfectly. Our coils have plenty of excess, so you can crimp the ends for a finished look. 8-MM PRE-SIZED COILS - These TruBind plastic coils measure 8mm, or 5/16 in diameter, for increased durability and holding strength. Easily bind books, documents, or reports in-office with pre-sized coils. BINDING CAPACITY - Our plastic coils can hold up to 54 sheets of standard 20# copy paper each when bound. That equals a maximum binding capacity of 9/32 inches in thickness, perfect for most office projects. 4:1 PITCH - Compatible with most 4:1 coil-binding machines, our plastic coils have 48 loops per 12-inch coil. Their 4:1 pitch matches the 4-holes-per-inch punching pattern on the side of your book.