Manufacturing and sales of ship machinery and equipment, outfitting parts, and ship accessories; manufacturing and sales of high and low voltage electrical equipment and accessories; mechanical processing design, manufacturing, and sales; manufacturing and sales of auto parts, motorcycle parts, engineering vehicle parts, and general machinery parts; sales of standard parts and instruments; self-operated and agent import and export business of various commodities and technologies (except for commodities and technologies that are restricted by the state or prohibited from import and export). General items: sales of metal materials; manufacturing of metal materials; sales of metal products; manufacturing of metal accessories for construction; sales of metal accessories for construction