Coil binding (or spiral binding as it's commonly called) is a very popular binding method, especially for things like calendars, cookbooks, and reports. ... Coil binding is also slightly more durable than comb binding, since the spine can't be opened and closed once it's been threaded through the punched holes.
What is a coil binding used for?
Coil binding, or “spiral binding,” as it's sometimes called, uses a piece of spiraled plastic or wire to hold the finished book together. Coil binding allows books to be laid flat when opened, or even folded over onto itself.