MULTIFUNCTION : One doorbell can be used with multiple B30/M6/M3 wifi doorbell, easy to use.VOLUME ADJUSTMENT : The wireless doorbell with different volume and different ringtones, you can adjust freely, bringing you a better experience. LOW POWER CONSUMPTION : The wifi doorbell bring you convenience, safe use , a good household supply. EXQUISITE GIFT : Modern fashion, beautiful and delicate, can be well integrated with your home decoration style.A good gift for a friend who loves household decoration, it is a great home decor. Specification: Material: ABS Color: Black Number of ringtones: 52 optional Ringer volume: 0-110 decibels, five-level adjustment, 0 decibels means silent flash mode Size: Approx. 83x83mm / 3.3x3.3in Weight: Approx.90g/3.2oz Voltage: 90~260V Package List:1 x Doorbell Installation Notes: Choose a suitable range from the video doorbell to install, and plug the receiver directly into a conventional power socket. After the installation is successful, you can press the transmitter and the indoor receiver will play music and flash. (Please tear off the protective film on the metal strip decoration before use) Pairing: Press the Dingdong volume button for 4 seconds, the LED light will light up. Then press the Wi-Fi video doorbell button within 5 seconds. When the Dingdong LED flashes quickly, the pairing is complete. Instructions for use: 1. Select music: After Dingdong is powered on, short press the previous music button on the right side to play the previous music, and short press the next music button to play the next music. A total of 52 eight-chord music can be selected, and it is repeated in a loop. 2. Learning mode music memory: Under the selected music, long press the volume button for 4 seconds, the music indicator light will be on and enter the learning state. At this time, press the Wi-Fi video doorbell button, the indicator light flashes quickly, and the memory is completed. After the above steps are completed, it will automatically exit the learning state. Note: One Dingdong can match 16 Wi-Fi video doorbells. One Wi-Fi video doorbell can handle countless Dingdongs at most. 3. Two or more music/Dingdong corresponding to the same Wi-F video doorbell: Long press the first Dingdong volume button for 4 seconds to enter the learning state, press the Wi-Fi video doorbell, and the pairing is successful within 5 seconds. Repeat the appeal operation to pair the selected Dingdong and this Wi-Fi video doorbell one by one. 4. Press and hold the volume button, and then plug it into the socket for 10 seconds, the LED light flashes quickly, it is clear that the pairing is successful.