Mini Alert Alarm

It works by means of Passive Infrared motion sensor which it detects a moving human body within a range of 8 meters x 80 degrees. The alarm sounds automatically when any human body approaches the detected zone. 20 degree vertical coverage allows you to position the alarm so pets will not set off alarm. A siren will sound for one minute then shut off automatically and reset itself. Visitor Chime Mode A pleasant "Ding Dong" melody sounds automatically to greet your visitor when they approach the detected zone. Uses 3 "AA" batteries, not included. LED indicator on face of infrared sensor alarm lights up when batteries are low and need replacing.