Download app "tuya" from app store to add the device to detect the status of your door / window, home security in your hand all the time Simply attach one piece to your door or window, and attach the other piece to the door or window frame Battery powered, convenient for you to replace the battery and easy for you to install with stickers Ideal intrusion warning for homes, apartments, mobile homes, dorms, offices, hotel rooms, garages, etc Low-consumption design, which can make it work long time