Wire-o (also refered to as twin loop or double loop wire) holds a book together using a 32 loop ( 3:1 pitch) or 21 loop (2:1 pitch) 11" length of wire. This method is popular as you are able to turn the book 360º and will lay perfectly flat - these featrues this make Wire-o ideal for used on calendars and note books.

Wire-o loops can be bent and compressed making this material less than ideal for items that will be used heavily or for long periods of time. Their are 5 standard colours for wire ( Black, White, Red, Blue, Silver) with sizes from 1/4" up to 1-1/4". Wires are produced at 3:1 pitch (3 holes per every one inch of paper) up 9/16" of diameter and 2:1 pitch ( 2 holes per every one inch of paper) from 5/8" and up.