The Tamerica TPW-3200 3:1 Wire Binding Machine is a basic model suitable for small office use. It can punch 12 sheets of 20# paper at a time with a 3:1 pitch pattern (3 holes per inch, 32 holes total). Its side margin adjustment helps center the punched holes within the edges of the page. Its punch depth adjustment can bring the holes closer to edge of the page or move them further away, depending on the total thickness of the book, in order to increase page tear resistance. Its open punch throat allows for punching pages that are larger than standard letter size. When pages are ready to be bound together, the wire holder on the machine will hold the wire spine in place as pages are loaded onto it. The built-in wire closer will bind books with wire spines up 9/16" in diameter.