34 APPARATUS AND DEVICES FOR HOME AND INDUSTRY-NAMELY, APPARATUS FOR VENTILATING, PURIFYING, HEATING AND COOLING AIR; HEATING AND COOLING COILS FOR SUCH APPARATUS; AIR DISTRIBUTION UNITS, AIR HUMIDIFIERS; AIR DEHUMIDIFIERS; AIR CONDITIONING UNITS, BOTH CENTRAL AND SELF-CONTAINED; RADIAL AIR FANS; AXIAL FANS; ROOF FANS; DUAL DUCT BOXES; EXHAUST HOODS FOR KITCHENS; SAUNA HEATERS; UNIT HEATERS; AIR CURTAINS; GRILLS AND REGISTERS FOR VENTILATION-NAMELY, EXTRACT VALVES, SUPPLY AIR VALVES, SUPPLY AIR DIFFUSERS, SUPPLY AIR UNITS, INDUCTION UNITS AND VENTILATION UNITS