Fellowes 5:1 pitch 16mm black metal binding spirals (100 units) 5110601 are designed to securely bind dense blocks of paper. The box of 100 units features a 16mm diameter, 5:1 pitch, and black-coated metal binding, capable of holding up to 130 A4 sheets. The classic black finish ensures a serious and durable presentation for formal meetings. They are suitable for law firms, accounting firms, and office filing.