Plug and Play-Wireless doorbell is easy to install and use, all you need to do is connect the receiver to a household power outlet and use the included 3M double-sided tape to install the transmitter box outside. Complete the installation in 3 minutes! Simple operation, no need to pull the warp, no need to drill the wall! 8 Levels Ultra-Volume Adjustable-Wireless doorbell uses the most stable music chip in the industry. It can pass through walls better to ensure a more reliable connection. There are 36 songs in the bell to choose from. You can use the music selection button to slide these 36 tracks, which can provide 8 volume levels. Press the music button once, the music will gradually increase from level 1-8. Wireless Long Range- Doorbell has 433MHz wireless frequency and super wide range, which n will not interfere with other appliances in the house. A single sufficient radio rate allows bells to be installed anywhere in the house. It is also an ideal replacement for traditional bells, traditional bells have been fallite and can alert elderly patients and nurses. Memory Loss Prevention Function-Wireless chime has a shutdown memory function, which will memorize the volume and selected music before shutdown, so there is no need to worry about information loss. Besides, the doorbell uses a low-power design which can save power and standby for a long time. LED Indicator Notify Person-When the wireless doorbell is connected to 220 AC, the outdoor Wi-Fi doorbell will ring the currently selected music and the LED will flash and enter the code pairing mode. If someone presses the bell, the doorbell will ring to make sure you don't miss any visitors or packages.