The motion sensor is powered by solar and built-in 9000mAh lithium battery , no wiring and no need replace the battery frequently. 1 alarm receiver can connect up to 32 sensors,and 1 sensor can be connected to unlimited alarm receiver ;it is the ideal for all types of indoor intrusion alarm application,such as front doors, window frames, driveways, walking paths, and anywhere in your home/office/stores/etc you want to be alerted.