Garage Door Monitorâ„¢ Sensor Model GS-101 LR ey pel The garage door monitorâ„¢ sensor is designed to monitor the status of your garage door and advise you if the door is open. By placing the sensor on the door panel, you: will be alerted when the door is open. When the garage door is open, receiver will beep and flash In this package, you should find a garage road monitorâ„¢ sensor, 3 lithium battery, double-sided foam tape, mounting accessories and a clip 3 Lithium a battery Double-sided foam taps.