9 FIRE ALARM AND FIRE SAFETY SYSTEM-NAMELY, ELECTRICALLY AND MECHANICALLY OPERATED DETECTORS AND ALARMS, MONITORS, SWITCH PANELS FOR FIRE DETECTOR SUPERVISION, ALARM BELLS AND HORNS, CONTROL STATION PUSH BUTTONS AND SWITCHES; MAT SWITCH CONTROLS; BELL TIMERS, AIR DUCT DETECTORS; TELEPHONE LINE BREAK INDICATORS AND SAFETY DEMONSTRATION KITS