Package Contents: 1 Transmitter, 1 Receiver Latest Technology and Battery-Free: This wireless doorbell is self-powered, requires no cables and batteries, protects the environment and saves money. When the transmitter is pressed, it generates electricity and sends a stable signal to the receiver. Never worry about damaging the wall or doorbell when changing the battery again! 38 Ringtones and 4 Volume Levels: Our wireless stereo doorbell speaker delivers rich and clear sound. It offers a wide range of 38 ringtones and 4 volume levels (including silent) for your personal taste. Press and hold the volume button to return to the first ringtone (dingdong). With a memory function, the radio clock remembers your last settings after a power outage. NO crosstalk and false alarm: This wireless doorbell has strong penetration power and anti-interference. The range over multiple obstacles is up to 152 m (500 ft) and in open areas up to 305 m (1000 ft). It will not interfere with other devices in your home or your neighbors, ensuring you never miss a visitor even if you are a few rooms away or on a different floor. < b>Easy Installation: Simply plug the mini receiver into an electrical outlet and mount the transmitter on a wall with the included hardware, including 2 screws and a piece of tape. < p> Our doorbell is suitable for homes, apartments, schools, villas, offices and more. This cordless doorbell without battery is a great Christmas, birthday or anniversary gift for any homeowner or business owner.