11 ENVIRONMENTAL CONTROL INSTALLATIONS FOR HEATING, VENTILATING AND AIR CONDITIONING PURPOSES, COMPRISING AIR TERMINAL BOXES, HIGH VELOCITY PRESSURE REDUCING BOXES, AIR VOLUME CONTROLLERS, THERMOSTATS, PRESSURE REDUCING VALVES, AIR VOLUME AND TEMPERATURE CONTROL UNITS, PLENUM UNITS, AIR DIFFUSER OUTLETS, GRILLER, REGISTERS, DIFFUSERS AND ASSOCIATED COMPONENTS, SOLD AS A UNIT