Air purifying apparatus and machines; Air cleaning filters (parts of air cleaning machines or installations); Air filtering apparatus; Air filtering installations; Filter housings (parts of water supply or sanitary installations); Filtering installations for air; Filters for dust; Filters for use with apparatus for sanitary purposes; Filters for use with apparatus for ventilating; Apparatus for ventilating; Mobile ventilating apparatus; Installations for ventilating; Filters for exhaust extractors (parts of ventilation installations); Extractors (ventilation or air conditioning); Ventilation grilles being parts of extractor fans