Easy to punch. Full Handle Sturdy Bar either for the left or right hand to punch easily. Manually punches 20 sheets of paper or 4 sheets of PVC covers at a time. Hands Free and Rapid Binding. Designed with Electric Coil Inserter, the spiral coil binding machine binds at most 80 sheets of papers at a time. It can be used at home, school and office quickly and easily. Accurate Punch Alignment. Utilizes a positioning knob to accurately place and position papers during the punching process. Suitable for Letter size, A4, and A5 sizes. Adjustable Margin Design. With adjustable Margin, the coil binding machine ensures a precise alignment with each document your bind, and you can easily customize the paper margin: 2.5mm, 4.5mm, 6.5mm to create professional-looking works