Air conditioning apparatus; Air cooling apparatus; Air-conditioning, air cooling and ventilation apparatus and instruments, namely, duct connector flanges, pipe flanges, ducting pipes, elbow hoses, duct reducers, pipe connectors, dryer vents, vent hoses, backdraft blockers and dampers, louvre grills, air vents, duct collars, exhaust hood vents, access panel doors, duct splitters, all of the aforementioned goods being integral parts of ventilation and air conditioning installations