AIR DISTRIBUTION GRILLES, REGISTERS, DIFFUSERS (FIXED OR ADJUSTABLE), VENTILATING LOUVERS, GRILLES, AIR VOLUME CONTROL DAMPERS, FIRE RELIEF AND BACKDRAFT DAMPERS, ROOF VENTILATORS, MANUAL AIR TURNING AND CONTROL DEVICES, LOUVER AND DAMPER BLADES AND PARTS THREFOR CONCERNED WITH THE CONDITIONING, CONTROL AND HANDLING AIR