The distinguishing characteristic of an industrial directory is that it lists products, services and suppliers needed by industries, rather than by final consumers. These would be mainly such intermediate products as automation equipment, CNC machining, transformers, advertising novelties, engineering services, leak detectors and a large variety of others. These intermediate products are used in making consumer products, or major projects such as space and ocean going ships, public utilities, defense requirements and so on.

While a few consumer products or dual use products might be listed, the emphasis in the industrial directories is on industrial products and services needed by other industries.