【215 Sheet Capacity】Plastic spiral binding coils measure 25mm(1") in diameter, can hold up to 215 sheets. They have been proven through testing reports and are capable of withstanding frequent use. 【4:1 Pitch & 48 Loops】Spiral binding coils have a 4:1 pitch, making them compatible with any binding machine that punches 4 holes per inch. (Attention: These 4:1 pitch binding coils are not compatible with the Cinch machine.) 【360-Degree Rotation】Plastic spiral binding coils provide a 360-degree page-turning rotation capability for easier reading, allowing bound projects to lay flat. 【For Letter Size】These 48-loop binding coils are suitable for letter-sized paper (8.5 x 11 Inches). The length can also be cut with Binditek coil crimpers pliers according to personal requirements. 【50 Binding Coils】Long-lasting and sturdy plastic spiral binding coils ensures long-term productivity for all your binding projects, allowing you to bind paper sheets with ease and store them for an extended period. Ideal for engineering files, business projects, office documents, and university presentations, they serve as amazing gifts suitable for teachers, students, and coworkers. Binditek 50 Pack Plastic Spiral Binding Coils, 25mm(1"), 215 Sheet Capacity, 4:1 Pitch, Black, 48 Loops, for Letter size, for Students and Coworkers