Wireless doorbell with batteries
Wireless doorbell for an apartment : Wireless Doorbell With Batteries
Quote from Article entitled Wireless doorbell for an apartment:
We should also mention an electric bell with a camera. It allows you to see who come to you in your absence. Pressing the button turns on automatically recording on a flash card or another date storage device. It should be installed where a good view on the zone in front of the entrance door will be provided. Devices with a camera can be relatively simple in design and equipped with additional functions and therefore more expensive.
The full version of the article can be found here.