XIANQI Useful Range of 300MOperating range can still reach up to 300m despite there are many obstacles (doors， walls). 38 Different Melodies & 3-Volume LevelsChoose easily by pressing the button on the receiver. Install the transmitter outdoors for convenient use. Operating temperature from -20 to 60， no worry about extreme weather . Easy Installation & Clear Flashing Plug the receiver into an electrical outlet (no batteries required for the main receiver) and mount the transmitter through double-sided tape or included screws/anchors. Doorbell without wire Tear off one side of the double-sided tape Tear off the other side of the double-sided tape And stick it on the bottom of the launcher And stick it on the wall outside the door PS: After the double-sided tape is stuck on the wall， don't let go， keep pressing the transmitter for 30 seconds， then release it. (It can be stuck to the wall more firmly). The transmitter can also be fixed with screws Wireless doorbell How to connect the transmitter to the receiver 1. Please select your preferred ringtone before connection. 2. Press the volume button for until the LED light flashes. 3. Press the button on the transmitter to send a signal to the receiver. Tip Before installation， received the transmitter's insulated plastic protective film and the transmitter to the receiver. Please do not install the transmitter on metal doors as the signal is not transferable. The range is reduced by fixed obstacles， especially steel， concrete walls and tall trees. getveryrich