40 Sheet Capacity: package includes 100 x black spiral binding coils spine inner diameter is 8mm(5/16 inch) can hold up to 40 sheets of paper easily add and subtract paper sheets perfect for most office projects 4:1 Pitch 48 Loops: the spiral binding coils are designed with a 4:1 pitch fit most binding machine that punches 4 holes per inch. Helping you combine your report pages calendars and documents providing convenience to your daily work Quality Material: the black binding coils are made of plastic sturdy and long-lasting capable of withstanding frequent use flexible to prevent snagging and cracking great for storing papers files or documents for a long time For Letter Size: the spiral binding coils are 31.5cm/12.4 inch in length suitable for letter sized paper (8.5 x 11 Inches) and standard A4 size paper (8.3x11.7") can can be also easily cut into the desired length according to your needs Keep Files Organized: the plastic binder coils can be used for storing office documents business presentations and engineering files keep messy documents organized and orderly. Suitable for teachers students and coworkers