Spiral plastic coil binding is a continuous PVC (plastic) filament formed into the shape of a spring (coil). Spiral coil  is spun, or threaded, into the document along the punched holes.  Plastic coil binding creates permanent lie-flat documents that turn 360 degrees. Plastic coil is used in a metric pitch,  the spacing of the metric holes leaves a little space  at the end of the sheet, so the last hole doesn’t tear out as easily. Metric patterns are more common than the non-metric although many people using the metric patterns refer to them as 4:1 or 5:1. The Plastic Spiral Coil we sell can be used with metric or non-metric holes. Order 5mm pitch for use with 5:1 punch patterns and 6mm pitch for use with 4:1. Crystal Clear or  matching color Poly Covers are available create professional documents. Plastic coil binding offers the utmost in flexibility with the ease of adding or deleting pages by simply by rebinding the book.