The Brinno DUO Peephole Doorcam works on 4 AA batteries; no wiring involved. It replaces the standard peephole so it can be installed even in rental apartments. Its unique Duo mode allows access both on its built-in screen and from this app at the same time! Every Brinno DUO door camera includes a knock sensor that activates the recorder when a visitor knocks on the door. It also supports up to 6 optional remote motion sensors. If you want it to, your Brinno DUO will send an email that include