CACAZI A80 1 For 1 Wireless Music Doorbell without Battery, Plug:US Plug 1. Material: ABS, electronic components 2. Remote control distance: 300 meters 3. Built-in music: 58 songs 4. Volume: 4-speed adjustment 5. Transmitter battery: a 12V23A battery (delivery without battery) 6. The doorbell has 58 built-in chord music, you can choose according to your preference 7. Strong penetrability, the straight-line distance on the open space can reach 300 meters (note: the actual use effect varies depending on the environment, and the signal receiving effect is also different due to different obstacles) 8. Working principle: The transmitter is installed outside the door, the receiver is installed on the power socket, press the transmitter to ring the bell, the receiver immediately rings and flashes to remind 9. Dimensions: Transmitter: 7.7 x 4.6 x 2 cm, Receiver: 9.5 x 6.5 x 3.3 cm