CellNock® is the ORIGINAL Smart Doorbell Peep Hole and easily replaces your peep hole or install it as a new one. The CellNock® P adds safety, privacy, and piece of mind to any home! You can even add CellNock® P at an entry wall, or your outside gate.Once installed you can receive alerts on your smart device when a visitor arrives and they press the call button. You will be able to accept or reject the call from your smart phone or tablet. You can see and talk to them, but they can not see you. You can also just monitor your visitor with the video camera. You do not need to be home to receive alerts or communicate with visitors, because you can just use your mobile device (internet connection required). The CellNock® P includes a wireless indoor doorbell chime. For use with an Android or iOS phone or tablet.