Physen Waterproof Wireless Doorbell,Operating Range at 1000 Feet,4 Adjustable Volume Levels with Over 50 Chimes,No Batteries Required for Main Receiver,White Expandable:self learning mode for you to DIY your house,2 reomte buttons for you to set receiver for different ringtones for different enters so you can know which doors is someone at. Doorbell can work within 1000 feet in open area.Generally,it can work within 200-700 feet through the metal security doors and walls depending on the specific using environment Remote push button is waterproof can accept for indoor or outdoor using environment,No matter is rain or snow weather adjustable volume levels from 30dB to 110dB and over 50 different ring tones with backward button and forward button for you easily to select the favorite music Easy install:just plug the receiver into outlet and use double-side adhesive tape at the back of the transmitter,also you can use the screw to install it.CE, FCC, RoHS certified