Rayson 5/16" Plastic Spiral Binding Coil, 40 Sheets Capacity, 4:1 Pitch 7.9mm Black Coil Binding Spines for Business and Educational Purposes, Pack of 100

Compact Capacity: Bind up to 40 sheets of 80g/20lb paper, ideal for smaller documents and light-duty projects.. Versatile: Compatible with U.S. letter size paper (8.5""x11"") or ISO standard A4 size paper (8.3""x11.7""). Length: About 12"" (48 Loops). The length can be easily adjusted to fit your needs using RAYSON coil crimper pliers. Durable Construction: Crafted from sturdy plastic, these coils are designed for long-lasting use. Great Value: Each pack includes 100 black coils, offering an affordable solution for bulk binding needs. 4:1 Coil binding ring means per inch has 4 holes (This is very important distinguish 3:1 from 4:1 cause the things to be as different. 3:1 means per inch has 3 holes. They are used with different binding machine.). Designed for 4:1 pitch coil binding machines, these spiral binding coils are ideal for reports, presentations, and office projects. A practical and thoughtful gift for professionals, educators, and students alike