Air filtering installations; Air filters for air conditioners in vehicle passenger compartments; Air purifying apparatus; Dental furnaces; Drying apparatus for use in heating, ventilation systems, air conditioning systems and refrigeration systems; Filters and filtering devices for air and gas conditioning; Filters for air conditioning; Filters for air extractor hoods; Filters, heaters and pumps sold in combination for use in swimming pools; Gas purification machines; Industrial air filter machines; Industrial electric oscillating fans for automatic cleaning of ceilings, light fixtures, ducts and other overhead structures exposed to fibrous airborne contaminants; Space heating apparatus; Ventilating fans for commercial and industrial use; Water filtration and purification units and replacement cartridges and filters therefor