Easy Installation: The latest upgrade wireless doorbell is a self-powered transmitter doorbell, without any battery, just plug the receiver into an electrical outlet, the push button transmitter can be stuck to the door with the provided adhesive strips. IP44 Waterproof Door Push Button: The waterproof rate of the door transmitter is IP44, used for rainy days or even special hot or cold weather with a working temperature of -30 to 70 degrees Fahrenheit; The waterproof is only for the doorbell push button. CE, FCC, RoHS certified. 400ft Long Wireless Range: You will be easily informed when someone is calling outside your house and never miss your valuable guests; 2 self-powered doorbell transmitter buttons and 2 plug-in home receivers have already been factory-paired so you can use them directly for your home Home Doorbell Receiver Button and Mode: This doorbell has two buttons to control the volume. The volume is 25-80db 1 to 38 music optional. Each time you press the mode button, you