Public address systems; Public-address systems and instruments; Public-address systems consisting of a control PC, digital amplification modules, volume button module, power bridge, frame for I/O cards and DSP cards, line interfaces, paging station, and paging station interface

heating, cooling, and ventilation equipment, namely, a hot and cold air blower, air conditioner and heater

COMMERCIAL HEATING, VENTILATING AND AIR CONDITIONING SYSTEMS