wire_binding

A popular commercial book binding method, and is known by various names, including double loop wire, double-o, ring wire, twin loop wire, wire comb, wire-o, wirebind and wiro. With this binding method, users insert their punched pages onto a C-shaped spine, and then use a wire closer to squeeze the spine until it is round. ("Wikipedia":https://en.wikipedia.org/wiki/Wire_binding)