Aerators [ventilation systems]; air purifying apparatus and machines; air vents [ventilation systems]; apparatus and instruments for ventilating purposes; apparatus for cleaning air; extractors [ventilation or air-conditioning]; filters for use with apparatus for ventilating; turbine ventilators [ventilation apparatus]; ventilating apparatus; ventilating fans; ventilation apparatus; ventilation dampers; ventilation hoods; ventilation installations; flues for ventilation apparatus; flumes for ventilation apparatus; flume and flashing systems for ventilation apparatus; parts, fittings, and accessories for the aforementioned