Plastic comb bindings are more vulnerable to damage than spiral bindings. They hold adjoining pages more tightly in register with each other than spiral bindings. They come in several colours and allow screen printing on a document's spine. They can bid pieces up to 3 inches thick.

Comb bindings allow pages to lie flat when opened. However, they cannot be doubled back. Inserting them is a hand operation that is quite costly for large numbers of documents.

A Wire-O binding holds the covers and pages of a document firmly in place by a double-loop wire inserted through holes drilled in their left edges. All of the document's pages lay flat when opened, can turn easily through 360°, and stay in perfect registration with adjoining pages.

Wire-O bindings come in nine standard colors and loop diameters from 3/16" to 1-1/4". They can handle documents from 1/8" to 1" thick. Often, they are used to bind reference books, reports, proposals, and calendars. They are durable, but do not permit printing on the document spine or the insertion of new pages.

To produce a perfect-bound document, the piece's folded signatures are gathered together in page sequence, clamped together, and placed in a machine that slices about 1/8" off their left edges. Then roughens mill the newly sliced sheet edges to prepare them for gluing. Finally, the edges receive an adhesive application and adhere to a backing.

Perfect binding is well suited for use with books, thick magazines, annual reports, technical manuals, and catalog's. From a minimum thickness of 1/8", it works well with a wide range of document thickness' and trim sizes. However, the paper used should not be heavier than 100 lb. Book stock, with the grain running parallel to the piece's spine.