Alarms, bells and buzzers installation and repair; anti-rust treatment for vehicles; billboard installation, maintenance and repair; boiler cleaning and repair; electric appliance installation and repair; electric motor apparatus and instrument installation, maintenance and repair; electric power supplying apparatus and instruments repair and maintenance; electronic appliances and equipment installation, and maintenance and repair; electronic communication machines and equipment installation, maintenance and repair; elevator installation and repair; film projector repair and maintenance; heat generating apparatus and instruments installation, maintenance and repair; heating equipment installation and repair; installation, maintenance and repair of computer hardware; interference suppression in electrical apparatus; lift installation and repair; lighting apparatus and instrument installation, maintenance and repair; loading and unloading apparatus and equipment installation, and repair; locks installation, maintenance and repair; measuring apparatus and instrument installation, maintenance and repair; medical apparatus and instrument maintenance and repair; motor vehicle maintenance and repair; office machines and equipment installation, maintenance and repair; painting or repair of signs; photographic apparatus repair; physical and chemical apparatus and instrument installation, maintenance and repair; printing and binding apparatus and equipment installation, maintenance and repair; pump repair; rebuilding engines that have been worn or partially destroyed; rustproofing; safe maintenance and repair; sterilization of medical apparatus and instruments; telephone installation and repair; tire repair; vehicle lubrication; vehicle maintenance; vehicle polishing; vehicle repair; vehicle service stations; vehicle wash and cleaning; water filtering apparatus installation, maintenance and repair; repair or maintenance of consumer electric appliances