Specially designed for the ProClick™ Pronto P3000 automatic binding system, ProClick™ Binding Spines take up to 145 sheets and are packed into 5 pre-loaded cartridges of 20, saving you valuable time. Documents fold back easily for perfect photocopying, and you can quickly edit them using a special tool to unzip the spine. A4 16mm. Pack size: 5 x 20 spine cartridges.