Fellowes 36mm 5:1 pitch metal binding spirals in black (25 units) 5111701 offer a reinforced solution for compiling extremely bulky blocks of paper. Comprising 25 units of 36mm in durable black metal with a 5:1 pitch, this pack allows you to bind up to 330 A4 sheets. The high-grammage metal maintains its shape even in heavy publications. Suitable for binding course manuals, legal codes and compendiums.