Electro-magnetic sensor that is activated when cars enter or exit the driveway. When a vehicle passes the sensor, the receiver emits an audible tone and an indicator light turns on. Used in combination with electric lock to add additional security. 400 Ft. range. Animals and people will not activate the driveway alert. Includes a low battery indicator on both the indoor receiver and transmitter. Requires (2) AA batteries, not included.
