Alarm sensors; Combustible gas concentration detectors; Fire alarm and emergency evacuation devices, namely, fire alarm control panels, smoke detectors, heat detectors, alarm pull stations, audible and visible notification appliances, strobes, sirens, bells, horns, and speakers; Gas alarms; Gas detectors for detecting the presence of gas; Gas sensors for measuring gas concentration; Gas testing instruments; Safety sensors, namely, carbon monoxide detectors, smoke detectors, and combination ca...