Eco-Friendly: Self-powered doorbell transmitter, there is a micro-generator in the transmitter that generates electric current and sends the signal to the receiver when pressed. No battery is required for this door chime. Long Range: The wireless doorbell is ideal for a range of up to 150m without signal loss and has strong anti-interference ability, which is very suitable for home use. Ringtone Setting: Choose your favorite sound from 38 different melodies. 4 adjustable levels between 0 dB and 80 dB. In addition, an optical LED signal appears when someone presses the doorbell. Easy to Install: Fix the doorbell to the wall with screws or double-sided tape and the receiver directly into a socket, No need for network or wiring IP65 Waterproof Doorbell: Strong waterproof, can install the doorbell (transmitter) outside the house; its working temperature is -20 °C to +60 °C; withstands bad weather