Easy Installation ♥ Two ways installation for push button, stick it with adhesive tape or mount it with screws and anchors, don\'t need any wire for installation, easy and convenient to use. Strong Working Signal Doorbells ♥ Works for most material door or wall, lncluding wood, glass, plastic, metal and more. Can be Used for Apartment, Office etc ♥ You can put them in living room/ bedroom/ kitchen/ backyard etc. Smart Memory Function ♥ Retain chime and volume settings during power outages, no need to configure doorbell settings again if unplugged. warm tips: ♥ The transmitter don\'t need battery, the receiver need to plug into the socket.