Ideal for placements on fences, balconies or by garage doors, Chuango AID-420 sensors work wonders in outdoor environments and detect acts of intrusion via invisible infrared beams. Through advanced technology and algorithms, only objects over a certain size would trigger an alarm with an instantaneous alert to your smartphone, minimizing false alarms. Completely wireless and battery-powered, Chuango AID-420 stands on guard for you in disguise, and the unique power-saving mode means up to 3 years of care-free, worry-free battery life.