37 Maintenance, installation, repair, upgrading, retrofit and refurbishment of industrial plants and machinery; maintenance, upgrade, retrofit, repair and upgrading of fans, extractor fans, dampers, blowers, compressors, circulators, gas circulators, manipulators, breakers, crushers, cooling, air conditioning, ventilating, heating and environmental control apparatus and installations, heat regenerators, air reheaters, incinerators, preheaters, heat exchangers, gearboxes and parts and fittings for all of the aforesaid; information, advisory and consultancy services relating to maintenance installation, repair, upgrading, retrofit and refurbishment of industrial plants and machinery; maintenance, upgrade, retrofit, repair and upgrading of fans, extractor fans, dampers, blowers, compressors, circulators, gas circulators, manipulators, breakers, crushers, cooling, air conditioning, ventilating, heating and environmental control apparatus and installations, heat regenerators, air reheaters, incinerators, preheaters, heat exchangers, gearboxes and parts and fittings for all of the aforesaid