Designed for apartments, commercial buildings, schools, motels, nursing homes, and factories that have existing fire alarms that give off an audible signal. This system was designed to supplement the existing fire bell system.The transmitter is wired to the existing hard-wired fire bell . A bulb or lamp is then plugged into the transmitter. When the existing fire bell is activated, the light attached to the transmitter will flash and FBR-72 wireless remote receivers will flash a lamp or activate a 120V bed shaker. The FBR-72 remote receivers can be plugged into any electrical outlet in the building. Easy installation!