【Binding Capacity】Binds up to 60 sheets of 20lb paper, with a 2.5mm margin for optimal capacity, ideal for smaller documents and light projects 【3:1 Pitch Design】Specifically designed for 3:1 pitch binding machines, featuring 3 holes per inch. This format differs from 4:1 pitch systems 【Versatile & Easy to Use】Compatible with U.S. Letter or A4 paper sizes, each coil is 12" long with 36 loops, and can be trimmed to fit using RAYSON wire coil crimper plier 【Durable Metal Construction】Made from high-quality metal, these wire coils ensure document longevity, allowing them to open flat and rotate 360 degrees for easy reading and copying 【Cost-Effective Pack of 100】Available in classic black, these coils offer a budget-friendly solution for binding projects in the office, school, or home RAYSON wire coil binding spines are built for durability and ease of use, making them an ideal choice for binding reports, presentations, and documents. Crafted from high-quality metal, these black coils enhance document longevity and allow them to open flat and rotate 360 degrees for easy reading and copying. With the ability to bind up to 60 sheets of 20lb paper, these coils are perfect for smaller to medium-sized projects. The margin size affects capacity, with a 2.5mm margin recommended for 60 sheets. Designed for 3:1 pitch binding machines (3 holes per inch), these coils are incompatible with 4:1 pitch systems. These versatile black coils work with any 3:1 pitch coil or wire binding machine, making them suitable for professional use at the office, school, or home. Each pack includes 100 coils, with 36 loops per coil, suitable for Letter and A4 size sheets. Excess wire can be easily trimmed as needed. RAYSON wire binding coils are clean, durable, and ensure secure binding. Whether using a RAYSON binding machine like the PT1202, TD-132, or TD-130, or binding by hand, these coils simplify the process for efficient results.