Binding Efficiency and Neatness: Our binding machine handles bulk projects effortlessly, punching up to 46 holes, 20 sheets, and binding 500 sheets at once. Ideal for schools, offices, and businesses, it ensures professionally finished documents. Compatible with Various Sizes: Featuring 46 detachable pins, this upgraded coil spiral binding machine allows you to insert large and non-standard page sizes. It's compatible with Letter size (42 holes), A4 size (46 holes), A5 size (33 holes), and more, ensuring versatility for various document bindings. Easy to Operate: Designed for user convenience, our coil binding machine features adjustable edge guides and side margins, and adjustable coil binding spine sizes from 1/4' to 2'. Using this electric coil binder saves time and energy compared to manual methods. Sturdy & Durable Material: Crafted with a cast iron base with a powder-coated surface, our book binder is robust and rust-resistant