Wire binding is available in three different hole formats or pitches. These three formats include Spiral-O, 2:1 pitch and 3:1 pitch (Wire-O).
Three-to-one pitch wire binding elements are used with machines that punch three holes per inch along an 11-inch side of paper. This type of wire is sometimes referred to as Wire-O binding.
Two-to-one pitch wire binding elements are used with machines that punch three holes per inch. The spacing is farther apart than 3:1 pitch and accomodates a few more pages.
Ninteen-ring wire uses the same hole pattern as comb binding. For this reason, this type of wire is sometimes referred to as wire comb binding. It is also called Spiral-O wire binding. This hole pattern has a total of 19 holes along the 11-inch side of a sheet of paper. This hole pattern is commonly found in dual format binding machines, which are machines capable of binding comb and wire.
Properties of this binding are:
Pages turn very easily and the book will lay completely flat.
Pages may also be opened back to back, while remaining flat.
Very durable. Excellent crush resistance.
Variety of colors available.