Smart voice doorbell, talk to the visitor via two-way voice, which allows you to know who is visiting your home, talk to them and let them know I am coming, please wait. * Compatible with rechargeable battery, the transmitter supports 4 AAA batteries which last up to 4 months (transmitter 4 AAA batteries not included). * 1 and 1 push button, talk between and push button via the connection within a large (outdoor bell: 200m indoor bell: 5-50m without any obstacle), stable transmission signal to make the voice clear. * Easy to install and use, the visitor presses the outdoor doorbell, after receiving the ringtone, you need to press once the button to connect, then long press to talk, release it when finished. * It is widely used for office and home, to know who is outside and convenient for the elderly who need much longer time to open the door, very practical.