Radio Frequency (RF) Pairing technology enables wireless connections between RF paired products.In addition to the audible sound from your smoke or heat alarms, the Strobe Light and Vibrating Pad will be triggered to alert those who may not be able to hear the audible alarm. The flashing strobe provides a visual warning for waking hours, while the vibrating pad is designed to be placed under a pillow or a mattress and is suitable for waking an individual to alert them when an alarm sounds.