Shake up to an alert to smoke, fire or carbon monoxide when sleeping with your hearing aid removed. The Medallion Series Shake-Up Receiver with Vibrator works with single or multiple Medallion Series smoke, fire transmitters or carbon monoxide detectors. When a transmitter signals a warning, the receiver activates a bed vibrator to awaken you and alert you to the potential danger. Position the bed vibrator between your mattress and box spring and place the receiver on your nightstand; it plugs into any standard 110-volt electrical outlet.