Double wire is a continuous metal wire that is formed into pairs of loops that are connected together to make up a binding element. The loops resemble a letter C when open and viewed from the end. After the pages are loaded onto the element, the wire is closed into a circular shape. Double Wire gives your books a very professional appearance, allows the pages to turn very easily, and lets the book lay completely flat when open. The pages remain aligned when opened so spreadsheets, charts, graphs, and illustrations that extend across the middle of the book will remain correctly aligned. Pages may also be wrapped around to the back of the book which marks your place in the book and gives it half the footprint, all while remaining flat. Many styles of Poly Covers may be used and a variety of materials can be combined in the same book. Standard Double wire bindings are 11″ long on the binding edge, and use 32 loops or holes or 21 depending on pitch. Double Wire also gives you the flexibility for multiple spaced binding. Where only sectional parts of the book is bound. Length and width of binding edges can also be customized for your particular project. Double Wire binding can be referred to by other names Ring-Wire® Bindings, Twin Loop Bindings, Double Loop Rings, Wire-O®
The double-loop spirals are produced “open” to be inserted in pre-punched holes of the suitable dimensions. Once inserted in the proper holes they are simply crimped closed with a wire closer. The 3 to1 (3:1) pitch is used for books up to about 1/2″ thick and 2 to 1 (2:1) wire can be used for books up to about 1-1/8″; However 2 to1 (2:1) can be also manufactured from 1/4″ to 9/16″ on demand.