37 Construction, installation, repair and maintenance services all such services relating to valves, common metals and their alloys, ironmongery and small items of metal hardware, manually operated valves made of metal, check valves made of metal, metal valves for controlling the flow of gases in pipelines, metal valves for controlling the flow of fluids or liquids in pipelines, nozzles made of metal, rods made of metal, tension levers made of metal, fasteners made of metal, nuts made of metal; construction, installation, repair and maintenance services all such services relating to bolts made of metal, screws made of metal, connectors made of metal, studs made of metal, valves being parts of machines, valves being parts of machine tools, hydraulic valves, pneumatic valves, valve closure mechanisms, valves to control flow, pressure, temperature and liquid level, valve wells, pressure regulators, valve wells, pressure controllers, pressure reducers, nozzles, turbines, silencers, sound absorbers; construction, installation, repair and maintenance services all such services relating to pumps, gears other than for land vehicles, gear boxes other than for land vehicles, gears for machines, gear units for machines, transmission gears for machines, gearbox casings for machines, gearbox casings other than for land vehicles, connecting rods for machines, motors and engines, hydraulic process control units, actuators, positioners, positioners as parts of machines; construction, installation, repair and maintenance services all such services relating to pneumatic industrial process controllers, ignition apparatus for machines, propulsion mechanisms other than for land vehicles, ignition apparatus for internal combustion engines, machine tools, machine coupling and transmission components (except for land vehicles), control and regulatory apparatus for fittings, electronic linear actuators, frequency converters, electric control valves; construction, installation, repair and maintenance services all such services relating to positioner sensors for use with machine tools and machines, limit switches, pressure switches, pressure regulators, electronic positioners as parts of machines, digital positioners as parts of machines, electric apparatus for remote ignition, control apparatus and instruments, regulating control apparatus and computer instruments, data processing equipment and computers, computer software; construction, installation, repair and maintenance services all such services relating to flow control and regulating apparatus and instruments, motion control and instruments, plumbing fittings and electrostatic precipitators, water pressure reducers, pressure controllers and regulators, industrial ventilation apparatus and instruments, cooling apparatus and instruments, regulators for level controlling in tanks, valves for use in cryogenic apparatus and equipment; construction, installation, repair and maintenance services all such services relating to flare stack systems for use in the oil industry burner control apparatus and instruments, flow control and regulating apparatus and instruments and parts and fittings for all the aforesaid goods