Wireless Plug-in Receiver: The portable wireless plug-in receiver connects to any standard outlet. The sensor uses 3 AAA batteries (not included). The infrared sensor detects motion and sends a signal to the receiver. The detection delay between the passage alarm is configurable from 15 seconds to 30 seconds, simply place the sensor at the entrance of your driveway and the receiver in your home. Sensitivity and Working DistanceThis motion sensor doorbell contains 2 motion sensors and 1 alarm receiver, the sensor can detect the movement of people and animals at 120, 7 meters, the work between the receiver and the sensor up to 200 meters. 4 Modes, 4 Volume Levels and 38 RingtonesThe motion sensor doorbell ringtone volume (0-80 dB) and ringtones can be adjusted according to your choice. Our doorbell has 38 melodic ringtones and 4 volume levels, choose the ringtone that suits you best. You can choose different modes and different volume levels for different occasions, more intuitive design. Wide Area CoverageThe weatherproof wireless motion sensor can be used to monitor and protect your outdoor/indoor property. The motion sensor doorbell works through thick walls, trees and buildings with metal coating. It doesn't interfere with other devices in your home or those of your neighbors and ensures that you won't miss any visitors, even if you're several rooms away.