Design and sales of rail transit vehicle equipment, trolleybus equipment, and other high-volume public transportation mobile equipment, traffic facilities, signals, and management systems; design, manufacturing, and sales of resistors, high-power electronic components, control cabinets, and load cabinets; computer software development and sales; self-operated and agent import and export of various commodities and technologies. General items: manufacturing of special equipment for oil drilling; manufacturing of generators and generator sets; manufacturing of computer software, hardware, and peripheral equipment; sales of special equipment for oil drilling; sales of generators and generator sets; retail of computer software, hardware, and auxiliary equipment