World-1st Mini PIR MP.Alert A9 Infrared Sensor Alarm Anti-theft Motion Detection GSM Alert with Infrared Inductive Probe (Black) Put the alarm cat or paste in a certain height, away from the body within 5 meters within the angular range 120  left and right, as long as people or animals, swaying back and forth in a very short time, induction start. Operating frequency: 850MHZ, 900MHZ, 1800MHZ, 1900MHZ;