KERUI 433MHz Home Wireless PIR Infrared Motion Sensor Detector for Alarm System Motion detector - The motion sensor can detect any movement within the detection range Works totally wireless - Does not need to be wired to the control center and the motion sensor has a root antenna can enhance the signal Can't work standalone - Work with KERUI security home alarm system Send alarm signal - It will send the alarm signal to control host once a alarm be triggered 1pcs battery required - 9V 6F22 battery powered and easy to install and operate