AIR CONDITIONING UNITS; VENTILATION FANS FOR DOMESTIC, COMMERCIAL AND INDUSTRIAL USE; HOUSING AND DUCT UNITS WITH HEATING, COOLING, AND HUMIDIFYING SECTIONS FOR DOMESTIC, COMMERCIAL AND INDUSTRIAL USE; INDUSTRIAL AND COMMERCIAL HEATERS COMPRISING AN ELECTRIC, GAS, OR HOT WATER HEAT SOURCE AND A HEAT EXCHANGER

air conditioning units; ventilation fans for domestic, commercial and industrial use; housing and duct units with [ HEATNG ] * HEATING * , COOLING, AND HUMIDIFYING SECTIONS FOR DOMESTIC, COMMERCIAL AND INDUSTRIAL USE; INDUSTRIAL AND COMMERCIAL HEATERS COMPRISING AN ELECTRIC, GAS, OR HOT WATER HEAT SOURCE AND A HEAT EXCHANGER

REGISTERS USED ON THE OUTLET OF AIR DUCTWORK