Comb binding

This method uses round plastic spines with 19 rings (for US Letter size) or 21 rings (for A4 size) and a hole puncher that makes rectangular holes.

Then the user chooses a spine size that will match the document.

The rings on the spine open and insert into the holes in the page, then rest against the body of the spine, resulting in a closure that can be opened again for making changes to the book.

With this bind, the book lies flat but cannot be opened 360 degrees.

For a book that can be opened such that the covers touch, a spine that does not have an obstructive body, such as a coil binding, is a better option.