Diamond Shape Indicator light graphics Doorbell Packge Include: transmitter receiver (do not include the battery) Product Feature: Product color: white/black Receiver size: 4.6x2.8x7.1cm Transmitter size: 3x1.5x6.5cm Receiver Working voltage: AC 110V-250V Music choices: 38 songs Volume: 5 levels Sensitivity: 110db Water resistant: IP55 Wireless distance: 150m(open space) Plug type for options: UK, EU, US, 1.The transmitter has a button, and the receiver has a diamond pattern. 2.The transmitter needs to be installed, and the receiver can be plugged into an indoor socket. 3.The transmitter Ourdoors sends out a signal, and the receiver sends out a sound after receiving the signal The installation is simple, no need to learn codes and complex operations.The transmitter is equipped with a battery, and the receiver can be used directly after plugging in the power.