Businesses involved in the treatment and coating of metals alter or protect the surfaces of metal components, parts and structures. Their work can improve resistance to corrosion, wear, heat or chemicals, change appearance, or prepare a surface for further manufacture. Customers may include manufacturers, engineering firms, construction businesses and owners of metal products requiring repair or refurbishment. Services can include galvanising, electroplating, anodising, powder coating, spray painting, metal spraying, polishing, passivation and chemical or heat treatments. Some firms specialise in particular metals, coating methods or component sizes, while others handle preparation as well as finishing, such as cleaning, degreasing, abrasive blasting and masking. Work may be carried out on individual items or production batches, with the process selected according to the metal, its intended use and the required finish.