Twin Loop(tm) Wire (sometimes called Wire-O binding) provides a durable book binding solution. Sometimes referred to as spiral binding, double loop wire binding or ring wire binding. This method provides a high-tech, contemporary presentation and books open a full 360 degrees, laying completely flat. Twin Loop Wire binding is also very durable and withstands temperature extremes.

1/4", 5/16" , 3/8", 7/16",1/2" ,
9/16",5/8",3/4",7/8",1"
Diameters 9/16" and smaller are 3:1 pitch, 32-hole; diameters 5/8" & larger are a 2:1 pitch, 21-hole