If your pets are always setting off your alarm system, try this motion sensor containing special technology to differentiate between humans and pets. A 3V battery is included. This PIR motion sensor recognizes pets under 3 ft. up to 80 lbs. Adjustable 1-3 pulse count allows you to set the number of beams that must be crossed before activating the sensor; set higher to prevent false alarms or lower for faster triggering of your alarm. LED on the unit can be turned on or off. 3-position vertical adjustment scale. 90 coverage at 40 ft.