Plug and Play - The wireless doorbell is easy to install and use. Simply connect the receiver to a household power outlet and use the included 3M double-sided tape to mount the transmitter outdoors. Complete setup in 3 minutes! Simple operation with no wiring or drilling required.8 Levels of Volume Adjustment - The wireless doorbell features a stable music chip that ensures reliable signal transmission through walls. Choose from 36 different melodies. Use the music selection button to scroll through the tunes, with 8 adjustable volume levels. Press the music button once to cycle through volume levels 1 to 8.Wireless Long Range - Operating at 433MHz, this doorbell offers a wide wireless range without interfering with other household devices. The strong radio signal allows flexible placement anywhere in your home. A reliable alternative to traditional doorbells, ideal for alerting elderly individuals or caregivers.Memory Loss Prevention - The wireless chime has a shutdown memory function that retains your selected melody and volume level after power-off, eliminating the need to reset preferences. Designed with low power consumption for extended standby and energy efficiency.LED Indicator Notification - When powered via 220V AC, the outdoor unit rings the selected melody and the LED flashes during code pairing mode. Once installed, pressing the doorbell button triggers the chime and activates the LED flash, ensuring you never miss a visitor or delivery.